4. Convenience sampling is an example of a. probabilistic sampling b. stratified sampling c. nonprobabilistic sampling d.

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1 1. Parameters are a. numerical characteristics of a sample b. numerical characteristics of a population c. the averages taken from a sample d. numerical characteristics of either a sample or a population 2. Sampling distribution of is the a. probability distribution of the sample mean b. probability distribution of the sample proportion c. mean of the sample d. mean of the population 3. The probability distribution of all possible values of the sample proportion is the a. probability density function of b. sampling distribution of c. same as, since it considers all possible values of the sample proportion d. sampling distribution of 4. Convenience sampling is an example of a. probabilistic sampling b. stratified sampling c. nonprobabilistic sampling d. cluster sampling 5. Which of the following is an example of nonprobabilistic sampling? a. simple random sampling b. stratified simple random sampling c. cluster sampling d. judgment sampling 6. Stratified random sampling is a method of selecting a sample in which a. the sample is first divided into strata, and then random samples are taken from each stratum b. various strata are selected from the sample c. the population is first divided into strata, and then random samples are drawn from each stratum d. None of these alternatives is correct. 7. A study was conducted to assess a new surgical procedure designed to reduce the incidence of post-operative complications. The incidence of complications was found to be 40% in 25 patients

2 having the new procedure and 60% in 20 patients having the old procedure. This difference was found to be not statistically significant. It may be concluded that a. The new procedure is effective in reducing post-operative complications b. The new procedure is ineffective in reducing post-operative complications c. The sample is biased d. The result is clinically significant 8. The closer the sample mean is to the population mean, a. the larger the sampling error b. the smaller the sampling error c. the sampling error equals 1 d. None of these alternatives is correct. 9. Since the sample size is always smaller than the size of the population, the sample mean a. must always be smaller than the population mean b. must be larger than the population mean c. must be equal to the population mean d. can be smaller, larger, or equal to the population mean 10. As the sample size increases, the a. standard deviation of the population decreases b. population mean increases c. standard error of the mean decreases d. standard error of the mean increases Answer of Multiple Choice Questions 1. (B) 2. (A) 3. (D) 4. (C) 5. (D) 6. (C) 7. (B) 8 (B) 9 (D) 10 (C) 1. A simple random sample from an infinite population is a sample selected such that a. each element is selected independently and from the same population b. each element has a 0.5 probability of being selected c. each element has a probability of at least 0.5 of being selected d. the probability of being selected changes 2. In point estimation a. data from the population is used to estimate the population parameter

3 b. data from the sample is used to estimate the population parameter c. data from the sample is used to estimate the sample statistic d. the mean of the population equals the mean of the sample 3. If we consider the simple random sampling process as an experiment, the sample mean is a. always zero b. always smaller than the population mean c. a random variable d. exactly equal to the population mean 4. The probability distribution of the sample mean is called the a. central probability distribution b. sampling distribution of the mean c. random variation d. standard error 5. The expected value of the random variable is a. the standard error b. the sample size c. the size of the population d. None of these alternatives is correct. 6. The standard deviation of all possible values is called the a. standard error of proportion b. standard error of the mean c. mean deviation d. central variation 7. The serum blood glucose was measured for a group of 20 diabetics, then an injection of insulin was given and after 2 hours another reading for blood glucose was recorded. To assess the effect of insulin in reducing the blood glucose level we conduct, a. Test of significance between two independent means b. The degree of freedom for the right test is 38 c. The paired t-test should be undertaken with degree of freedom of 38 d. The paired t-test with a degree of freedom should be carried out

4 8. As the sample size becomes larger, the sampling distribution of the sample mean approaches a a. binomial distribution b. Poisson distribution c. normal distribution d. chi-square distribution 9. Whenever the population has a normal probability distribution, the sampling distribution of is a normal probability distribution for a. only large sample sizes b. only small sample sizes c. any sample size d. only samples of size thirty or greater 10. The sampling error is the a. same as the standard error of the mean b. difference between the value of the sample mean and the value of the population mean c. error caused by selecting a bad sample d. standard deviation multiplied by the sample size Answer of Multiple Choice Questions 1. (A) 2. (B) 3. (C) 4. (B) 5. (D) 6. (B) 7. (C) 8 (C) 9 (C) 10 (B) 1. Which of the following is considered to be a more efficient estimator? a. sample median b. sample mode c. sample mean d. any measure of central location 2. A population characteristic, such as a population mean, is called a. a statistic b. a parameter

5 c. a sample d. the mean deviation 3. A property of a point estimator that occurs whenever larger sample sizes tend to provide point estimates closer to the population parameter is known as a. efficiency b. unbiased sampling c. consistency d. relative estimation 4. A sample statistic, such as a sample mean, is known as a. a statistic b. a parameter c. the mean deviation d. the central limit theorem 5. The standard deviation of a point estimator is called the a. standard deviation b. standard error c. point estimator d. variance of estimation 6. A single numerical value used as an estimate of a population parameter is known as a. a parameter b. a population parameter c. a mean estimator d. a point estimate 7. A theorem that allows us to use the normal probability distribution to approximate the sampling distribution of sample means and sample proportions whenever the sample size is large is known as the a. approximation theorem b. normal probability theorem c. central limit theorem d. central normality theorem

6 8. A property of a point estimator that occurs whenever the expected value of the point estimator is equal to the population parameter it estimates is known as a. consistency b. the expected value c. the estimator d. unbiasedness 9. A simple random sample of size n from an infinite population of size N is to be selected. Each possible sample should have a. the same probability of being selected b. a probability of 1/n of being selected c. a probability of 1/N of being selected d. a probability of N/n of being selected 10. For a population with any distribution, the form of the sampling distribution of the sample mean is a. sometimes normal for all sample sizes b. sometimes normal for large sample sizes c. always normal for all sample sizes d. always normal for large sample sizes Answer of Multiple Choice Questions 1. (c) 2. (b) 3. (c) 4. (a) 5. (b) 6. (d) 7. (c) 8 (d) 9 (a) 10 (d) 1. The absolute value of the difference between the point estimate and the population parameter it estimates is the a. standard error b. sampling error c. precision d. error of confidence e. None of the above answers is correct. 2. The confidence associated with an interval estimate is called the a. significance

7 b. degree of association c. confidence level d. precision 3. A probability statement about the sampling error is known as the a. confidence b. precision c. interval d. error 4. In a study about hemoglobin level in pregnant and non-pregnant women, the mean levels in the two groups were 12 gm/100ml and 14gm/100ml respectively. A test of significance between the means of the two groups was carried out and the difference was found significant at p<0.05, this means that the difference a. May be attributed to chance b. Could be random c. Is true and is unlikely to be by chance d. Cannot be tested due to insufficient data 5. As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution a. becomes larger b. becomes smaller c. stays the same d. None of the above answers is correct. 6. A clinical trial was designed to test the efficiency of a medicine to reduce the systolic blood pressure. A group of 20 hypertensive patients were randomly selected and their blood pressure was recorded. The medicine was administered and a second reading was recorded from the same group of patients. The convenient test of significance to be conducted is: a. One proportion Z-test b. Paired t-test c. Independent t-test for two means d. Two proportion z-test 7. The mean difference at 0.01 (significant level ) is:

8 a. Statistically significant difference b. Not statistically significant difference c. Attributed by chance d. Equal 8. An estimate of a population parameter that provides an interval of values believed to contain the value of the parameter is known as the a. confidence level b. interval estimate c. parameter value d. population estimate 9. The difference between the point estimate, such as the sample mean, and the value of the population parameter it estimates, such as the population mean, is known as the a. confidence level b. sampling error c. parameter estimate d. interval estimate 10. The mean difference at 0.05 (significant level ) is: a. Statistically significant difference b. Not statistically significant difference c. Attributed by chance d. Equal Answer of Multiple Choice Questions 1. (b) 2. (c) 3. (b) 4. (c) 5. (b) 6. (b) 7. (b) 8 (b) 9 (b) 10 (a) 1. Whenever the population standard deviation is unknown and the population has a normal or near-normal distribution, which distribution is used in developing an interval estimation? a. standard distribution b. z distribution c. beta distribution d. t distribution

9 2. The relationship between α and β is a. Direct b. Indirect c. No relation d. all of these 3. The only way to reduce β and α simultaneously is to a. Increase sample size b. Increase variance c. Increase P-value d. all of these 4. The relationship between the power and α is a. Direct b. Indirect c. No relation d. none of these 5. The power increases as sample size a. Increasing b. Decreasing c. Constant d. all of these 6. In developing an interval estimate, if the population standard deviation is unknown a. it is impossible to develop an interval estimate b. the standard deviation is arrived at using historical data c. the sample standard deviation can be used d. None of the above answers is correct. 7. In order to use the normal distribution for interval esti population

10 a. must be very large b. must have a normal distribution c. can have any distribution d. None of the above answers is correct. 8. From a population which is not normally distributed and whose standard deviation is not a. The normal distribution can be used. b. The t distribution with 19 degrees of freedom must be used. c. The t distribution with 20 degrees of freedom must be used. d. The sample size must be increased. 9. A sample of 100 elements from a population is selected, and the standard deviation of the a. normal distribution b. t distribution with 100 degrees of freedom c. t distribution with 99 degrees of freedom d. None of the above answers is correct. 10. From a population that is normally distributed, a sample of 25 elements is selected and the standard deviation of the sampl distribution to use is the a. normal distribution b. t distribution c. t distribution with 26 degrees of freedom d. t distribution with 24 degrees of freedom Answer of Multiple Choice Questions 1. (d) 2. (b) 3. (a) 4. (a) 5. (a) 6. (c) 7. (b) 8 (d) 9 (a) 10 (d) 1. If the P-value = 0.25, this means that a. evidence supports the null hypothesis b. There is evidence to reject the null hypothesis c. There is a strong evidence to reject the null hypothesis

11 d. There is a very strong evidence to reject the null hypothesis 2. The mean height of boys with sickle anemia is a. Statistically significant different from the 86.5 b. Not statistically significant different from the 86.5 c. Attributed by chance d. Equal to As the sample size increases, the sampling error a. increases b. decreases c. stays the same d. None of the above answers is correct. 4. For which of the following values of P is the value of P(1 - P) maximized? a. P = 0.99 b. P = 0.90 c. P = 0.01 d. P = A 95% confidence interval for a population mean is determined to be 100 to 120. If the a. becomes narrower b. becomes wider c. does not change d. becomes 0.1 e. None of the above answers is correct to If the level of significance is decreased, the interval for the population proportion a. becomes narrower b. becomes wider c. does not change d. Not enough information is provided to answer this question. e. None of the above answers is correct.

12 7. The ability of an interval estimate to contain the value of the population parameter is described by the a. confidence level b. degrees of freedom c. precise value of the population mean d. None of the above answers is correct. 8. After computing a confidence interval, the user believes the results are meaningless because the width of the interval is too large. Which one of the following is the best recommendation? a. Increase the level of confidence for the interval. b. Discard the current data and try a different sample. c. Increase the sample size. d. Reduce the population variance. 9. If we change a 95% confidence interval estimate to a 99% confidence interval estimate, we can expect a. the size of the confidence interval to increase b. the size of the confidence interval to decrease c. the size of the confidence interval to remain the same d. the sample size to increase 10. In general, higher confidence levels provide a. wider confidence intervals b. narrower confidence intervals c. a smaller standard error d. unbiased estimates Answer of Multiple Choice Questions 1. (a) 2. (a) 3. (b) 4. (d) 5. (a) 6. (b) 7. (a) 8 (c) 9 (a) 10 (a) 1. As a solution to his criticisms of null hypothesis testing, Loftus (1991;1996) suggested that

13 researchers should make it their practice to report confidence intervals alongside their statistical tests. A. True B. False 2. The null hypothesis is: A. the assumption that a significant result is unlikely. B. the assumption there is no relationship or difference between the variables you are testing. C. the assumption that there is a relationship or difference between the variables you are testing. D. the pattern between the variables you are testing. 3. Even if there is no real relationship between variables in the population, it is highly likely that you will find a relationship between variables in your randomly selected sample. A. True B. False 4. How can p<.05 be interpreted? A. There is a 5% chance of you making a type one error. B. There is a less than 1 in 20 probability of the result occurring by chance alone if the null hypothesis were true. C. The probability of obtaining the data if the null hypothesis were true is less than 5%. D. All of the above. 5. Hypothesis: Higher levels of depression are related to higher levels of anxiety. Considering this research hypothesis, what would the null hypothesis be? A. Individuals with lower levels of depression will have higher levels of anxiety. Any result otherwise observed is the product of chance. B. There is no relationship between depression and anxiety. Any observed relationship is the result of chance. C. There will not be a significant difference between those individuals who score high on depression, in comparison to those individuals who score high on anxiety. Any observed difference is the result of chance alone. D. Individuals with higher levels of depression will have lower levels of anxiety. Any relationships otherwise observed are the result of chance alone.

14 6. Hypothesis: Individuals who listen to music whilst revising will achieve significantly higher exam grades than will individuals who do their revision in silence. Thinking about this research hypothesis, which of the below would be an appropriate null hypothesis? A. There will be no difference in exam grade between those individuals who revise whilst listening to music and those individuals who revise in silence. Any observed differences are due to chance alone. B. Individuals who listen to music whilst revising for their exam will achieve significantly lower exam grades than will individuals who revise in silence. C. There will be no relationship between examination grade and the amount of music or silence experienced during revision. Any observed relationship is the product of chance alone. D. The more music an individual listens to when they are revising, the higher their exam grade will be. In addition, the more silence an individual experiences whilst revising, the lower their exam grade will be. 7. If you decided to make the critical p-value for significance as opposed to the conventional level of 0.05, what would the consequences be? A. You would be less likely to make a type one error. B. There would be fewer instances when the null could be rejected. C. You would be more likely to make a type two error. D. All of the above. 8. Loftus (1991; 1996) criticised hypothesis testing. What was his criticism? A. Loftus' criticism was that the null hypothesis always states that there is no relationship. The actual chance of no relationship at all being found is very unusual even in biological sciences. To base probability judgments on this hypothesis is misleading. B. Loftus' criticism was that it is difficult for researchers to test the null hypothesis when they cannot access exact p values consistently. The results reported are therefore misleading. C. Loftus' criticism was that reporting descriptive statistics and confidence intervals is misleading when testing the null hypothesis. D. Loftus' criticism was that the null hypothesis always states that there is a relationship. The actual chance of a relationship at all being found is very unusual even in biological sciences. To base probability judgments on this hypothesis is misleading. 9. Look at the hypothesis described in question 7. What are the dependent and independent variables?

15 A. The independent variable is exam grade and the dependent variable is revision condition. B. The independent variable is revision condition and the dependent variable is exam grade. C. The independent variable is silence and the dependent variable is exam grade. D. The independent variable is music and the dependent variable is silence. 10. One of the problems we face when conducting research is that when we select samples from populations, we might not get a sample that accurately reflects that population. A. True B. False Answer of Multiple Choice Questions 1. (A) 2. (B) 3. (B) 4. (D) 5. (B) 6. (A) 7. (D) 8 (A) 9 (B) 10 (A) 11(D) 1. Sometimes, due to, we are likely to get patterns of scores in our samples that do not accurately reflect the underlying population. A. sampling error B. scattergrams C. probability D. relationships between variables 2. The p-value is sometimes misinterpreted. It represents the probability of a relationship occurring by chance if the null hypothesis is true. Therefore it assumes that the null is true. A. True B. False 3. The second criticism Loftus (1991; 1996) raised was that psychologists don't give enough consideration to the when reporting their results. A. exact p value B. statistical tests C. null hypothesis D. population means 4. What does a p-value generally tell us?

16 A. The p-value tells us the likelihood of our obtaining the pattern of results due to sampling error if there is not a relationship between our variables in the population. B. The p-value tells us the likelihood of our obtaining the significant result due to a relationship between our variables in the population. C. The p-value tells us the likelihood of our obtaining the pattern of results due to variance if there is not a relationship between our variables in the population. D. The p-value tells us the likelihood of our obtaining the pattern of results due to sampling error if there is a population. 5. What is a type one error? A. A type one error is obtaining a non-significant result by sampling error alone. B. A type one error is where we reject the null hypothesis when it is true. C. A type one error is obtaining a non significant result when it should be significant. D. None of the above. Answer of Multiple Choice Questions 1. (A) 2. (A) 3. (D) 4. (D) 5. (B)