Chapter 9 quiz

Given a population mean of 8.7, a sample mean of 7.2, and an estimated standard error of .50, calculate the single sample t value. A. -3.00 B. +3.00 C. 31.80 D. impossible to calculate without sample size

A

If the standard deviation for a population, as estimated from a sample, is s = 5.6, then the standard error for a sample size of N = 16 is: A. SM = 1.40. B. SM = 0.35. C. SM = 1.45. D. SM = 0.37.

A

A newspaper article reported that the typical American family spent an average of $81 for Halloween candy and costumes last year. A sample of N = 16 families this year reported spending a mean of M = $85, with s = $20. Do these data indicate a significant change in holiday spending? (Hint: $81 would be considered the population mean.) A. t=.80 Do not reject the null hypothesis. The difference is not statistically significant. B. t=.80 Reject the null hypothesis. The difference is statistically significant. C. t=.20 Do not reject the null hypothesis. The difference is not statistically significant. D. t=.20 Reject the null hypothesis. The difference is not statistically significant

A

A newspaper article reported that the typical American family spent an average of $81 for Halloween candy and costumes last year. A sample of N = 16 families this year reported spending a mean of M = $85, with s = $20. What statistical test would we use to determine whether these data indicate a significant change in holiday spending? (Hint: $81 would be considered the population mean.) A. single-sample t test B. z test C. independent-samples t test D.dependent-samples t test

A

A researcher is interested in whether infants' attention to their mothers' voices increases in the first week of life. The researcher selects 15 full-term infants in normal health who experienced uncomplicated deliveries and tests the number of seconds the infants oriented in the direction of their mother's voice on Day 1 and on Day 7 after delivery. The fictional data follow. What are your conclusions? (As in the problem above, the group size should ideally be greater than 30. These numbers were kept down to simplify calculations. Also, because it would be unlikely that these infants were randomly selected, the researcher should be cautious in generalizing the results.) Day 1 Day 7 6 7 5 7 3 6 8 8 6 8 6 8 6 8 7 8 8 6 5 7 6 7 7 7 5 7 6 8 4 6 A. t=4.183. Reject the null hypothesis at the .01 level of significance for both a one-tailed and a two-tailed test. The average number of seconds attending to mother's voice on Day 7 is greater than on Day 1. B. t=4.183. Do not reject the null hypothesis at the .05 level of significance. The average number of seconds attending to mother's voice on Day 7 is similar to that on Day 1. C. t=1.874. Reject the null hypothesis at the .01 level of significance, for a two-tailed but not a one-tailed test. The average number of seconds attending to mother's voice on Day 7 differs from that on Day 1. D. t=1.874. Do not reject the null hypothesis at the .05 level of significance. The average number of seconds attending to mother's voice on Day 7 is similar to that one day

A

A researcher wondered if his new relaxation training method would result in better than average results in helping people to stop smoking. He recorded the average number of cigarettes smoked for his 25 patients immediately before undergoing the relaxation training program and again six months after completing the program. The degrees of freedom for this test is ________. A. 25 B. 24 C. 50 D. 48

B

A researcher wondered if his new relaxation training method would result in better than average results in helping people to stop smoking. He recorded the average number of cigarettes smoked for his 25 patients six months after undergoing the relaxation training program and compared this to the national average for all smoking cessation programs. Imagine the results of his test are as follows: t(24) = 1.24, p > 0.05. Which of the statements below would logically follow? A. The relaxation training program resulted in patients smoking less than average. B. The relaxation training program did not result in reduced smoking rates. C. The researcher most likely made a Type I error. D. The researcher rejected the null hypothesis.

B

Another name for a paired-samples t test is: A. single-sample t test. B. dependent-samples t test. C. independent-samples t test. D. no-sample t test.

B

The correct formula for using the sample standard deviation to estimate the population standard deviation. a. has N in the denominator. b. has (N-1) in the denominator C. has N2 in the denominator D. Has N in the numerator

B

The difference between the denominator of the z test and that of the single sample t test is that: A. in the z test we divide by the estimated standard error, but in a t test we divide by the actual standard error. B. in the z test we divide by the actual population standard error, but in a t test we divide by the estimated standard error. C. in the t test we divide by the actual population standard deviation, but in a z test we divide by the sample standard deviation. D. in the t test we divide by the sample standard deviation, but in a z test we divide by the population standard deviation.

B

The method for calculating s will result in a ________ value as compared to SD. A. smaller B. larger C. more negative D. less accurate

B

What type of statistical test would we use to compare a sample to a population for which we know the mean but not the standard deviation? C. z test B. single sample t test C. paired samples t test D. independent samples t test

B

A study by Bettmann (2007) published in the Journal of the American Psychoanalytic Association assessed whether the attachment relationships between adolescents and their parents change as a result of a residential wilderness treatment experience for the adolescents. Participants completed the Adolescent Attachment Questionnaire at the start and at the end of the wilderness program. Which of the following would be the null hypothesis for this study? A. Adolescents will have stronger attachment relationships to their parents after the wilderness experience. B. Adolescents will have a different attachment relationship with their parents after the wilderness experience. C. There will be no difference in attachment relationships after the wilderness experience. D. Adolescents will have weaker attachment relationships to their parents after the wilderness experience.

C

As sample size increases, the t distribution: A. is unreliable. B. has a standard deviation of 0. C. becomes similar to the z distribution. D. has a standard deviation of 0.50.

C

If our critical value for t is 2.015 and our calculated test statistic is 2.20, what should we conclude? A. that our effect is large B. that our effect is small C. reject the null hypothesis D. fail to reject the null hypothesis

C

The formula "H0: µ1 = µ2" is used to represent the: A. alternative hypothesis B. research hypothesis C. null hypothesis standard error

C

The symbol representing a standard deviation calculated by using a sample to estimate the population standard deviation is: A. sd. B. the Greek letter 'sigma'. C. s. D. Std. Dev.

C

Which of the following reports of statistical results are in appropriate APA format? A.t = 1.2, df = 5, fail to reject null B. t = 1.2, df = 5, reject null C. t(5) = 1.2, p > 0.05 D. t = 1.2, df = 5, , p > 0.05

C

With very few degrees of freedom, the test statistic: A. becomes more reliable. B. employed should be a z test rather than a t test. C. needs to be more extreme to reject the null hypothesis. D. needs to be less extreme to reject the null hypothesis.

C

n a within-groups design in which each research participant is measured under two different conditions, the appropriate hypothesis test is a(n): A. single-sample t test. B. two-way analysis of variance. C. paired-samples t test. D. independent-samples t test

C

A study by Bettmann (2007) published in the Journal of the American Psychoanalytic Association assessed whether the attachment relationships between adolescents and their parents change as a result of a residential wilderness treatment experience for the adolescents. Participants completed the Adolescent Attachment Questionnaire at the start and at the end of the wilderness program. What statistical test would we use to determine whether the wilderness treatment affected attachment relationships? A. single-sample t test B. z test C. independent-samples t test D. paired-samples t test

D

Hout, Duncan, and Sobel (1987) reported on the relative sexual satisfaction of married couples. They asked each husband and wife of 91 married couples to rate the degree to which they agreed with the statement "Sex is fun for me and my partner." What statistical test would we use to determine whether there is, on average, a difference in the sexual satisfaction of husbands and wives? A. single-sample t test B. z test C. independent-samples t test D. paired-samples t test

D

In a fictional study, a pretest-posttest design was used to examine the influence of a television program on children's aggressiveness. The number of aggressive responses was measured during an observation period both before and after the television program. Test the hypothesis using the following data to determine if there is a difference in the number of aggressive behaviors in children after having viewed the television program. (Note: Ideally, the group size should be greater than 30. These numbers were kept down to simplify calculations. Also, because it would be unlikely that these children were randomly selected, the researcher should be cautious in generalizing the results.) Participant Before After 1 6 9 2 4 3 3 12 11 4 9 12 5 10 14 6 2 6 7 14 12 A. t(6) = 2.657, p < 0.05. We reject the null hypothesis. The number of aggressive behaviors exhibited after watching a television program differs from the number exhibited prior to watching the television program. B. t(6) = 2.657, p > 0.05We do not reject the null hypothesis. We have no evidence that the number of aggressive behaviors exhibited after watching a television program differs from the number exhibited prior to watching the television program. C. t(6) = 1.433, p < 0.05. We reject the null hypothesis. The number of aggressive behaviors exhibited after watching a television program differs from the number exhibited prior to watching the television program. D. t(6) = 1.433, p > 0.05. We do not reject the null hypothesis. We have no evidence that the number of aggressive behaviors exhibited after watching a television program differs from the number exhibited prior to watching the television program.

D

It is more difficult to reject the null hypothesis when: A. you have a larger as opposed to a smaller sample size. B. you have paired-samples t rather than an independent-samples t. C. using a single-sample t rather than an independent-samples t. D. using a two-tailed test rather than a one-tailed test.

D

The t statistic indicates the: A. number of standard deviations an individual score is from the sample mean. B.number of standard deviations a sample is from the population mean. C. distance of two sample means from a single population mean. D. distance of a sample mean from the population mean in terms of estimated standard error.

D