# Question 1 The mean number of close friends for the population freshman college students in the U.S.A. is µ = 5.7. The standard deviation of scores in this population is σ = 1.3. A psychologist

Question 1

The mean number of close friends for the population freshman college students in the U.S.A. is   µ = 5.7. The standard deviation of scores in this population is  σ = 1.3.  A psychologist predicts that the mean number of close friends for freshman introverts will be significantly different from the mean of the population. The mean number of close friends for a random sample of 25 freshman introverts is M = 6.5.  With a = .05, determine the critical value of z* or t* that needs to be employed here.  The value of the appropriate of  z* or t* is:  1.65

A. 1.711

B. 1.96

C. 2.060

D. 2.064

E. the correct value of z* or t*  is not listed in alternatives “a” through “e”

Question 2

A sleep researcher hypothesizes that college students who are deprived of sleep will perform significantly lower on tests of cognitive ability than the general student body who likely slept around eight hours. One standardized test of cognitive ability, called the STCA, reveals that mean score for college students who slept around eight hours is µ = 4.5.  Scores on the STCA range from 1-9 with high scores indicating better performance.  The researcher brings 15 volunteer participants into the sleep lab one night and limits their sleep to four hours. The next morning he administers the STCA. Their scores are below. 2,  3,  3,  2,  5,  3,  3,  3,  6, 7,  2, 5,  4,  3,  4With α = .05, determine the critical value of z* or t* that needs to be employed here.  The value of the appropriate of  z* or t* is: A.  1.65

B. 1.753

C. 1.761

D.  2.133

E.  2.33

F.  the correct value of z* or t*  is not listed in alternatives “a” through “e”

Question 3

A sleep researcher hypothesizes that college students who are deprived of sleep will perform significantly lower on tests of cognitive ability than the general student body who likely slept around eight hours. One standardized test of cognitive ability, called the STCA, reveals that mean score for college students who slept around eight hours is µ = 4.5.  Scores on the STCA range from 1-9 with high scores indicating better performance.  The researcher brings 15 volunteer participants into the sleep lab one night and limits their sleep to four hours. The next morning he administers the STCA. Their scores are below. 2,  3,  3,  2,  5,  3,  3,  3,  6, 7,  2, 5,  4,  3,  4Set your alpha level at α = .05.  Complete steps 3 and 4 of the hypothesis testing procedure.What decision should the researcher make about sleep deprivation and cognitive performance as measured with the STCA?

A.  The researcher should reject H0 and conclude that sleep deprivation improves cognitive performance

B.  The researcher should retain HA and conclude that sleep deprivation makes no difference in cognitive performance

C.  The researcher should reject H0 and conclude that sleep deprivation makes no difference in cognitive performance

D. The researcher should reject HA and conclude that that sleep deprivation impairs cognitive performance

E. The researcher should reject H0 and conclude that sleep deprivation impairs cognitive performance

Question 4

Weight loss programs are abundant in the U.S.A.  Some cost a membership fee, some do not. But all seem to work (at least temporarily) if the individual “complies” with the program for at least 60 days. Presume that the mean weight loss after 60 days for the population of adults complying to a program, any program, is µ  = 15 pounds, with a standard deviation of  σ = 4.0.  You have developed a novel program combining “clean-eating” plus daily aerobic exercise and predict that persons in your program will lose more weight than the national average of 15 pounds in 60 days.  Eighteen adults participate in your program and at the end of 60 days have a mean weight loss of  M = 15.83 pounds.   Set your alpha level at α = .05.  Complete step 3 of the hypothesis testing procedure and calculate z or t,  whichever is appropriate for these data.  Round to the nearest hundredths place.  If your calculated z or t is not identical to one of the values below, but within plus or minus 0.2 of an answer below, assume it’s a rounding error and select the answer that is closest to your calculated value.  Ignore the minus sign if your calculated z or t is negative.

A.   .66

B.  .88

C. 1.88

D.  3.77

E.  4.05

F. the correct value of z or t is not listed in alternatives “a” through “e”, even when taking into   consideration a rounding error of plus or minus 0.2.

Question 5

The mean number of close friends for the population freshman college students in the U.S.A. is  µ= 5.7. The standard deviation of scores in this population is σ  = 1.3.  A psychologist predicts that the mean number of close friends for freshman introverts will be significantly different from the mean of the population. The mean number of close friends for a random sample of 25 freshman introverts is M = 6.5.  Which  hypothesis test needs to be employed here, the  z test or the one-sample t test?

A. z test

B. one-sample t test

Question 6

Blood pressure is measured in millimeters of mercury (mm Hg) and recorded with the systolic number first, followed by the diastolic number. The normal mean systolic blood pressure of female college students is µ  = 120 mm Hg.  You are a physiological psychologist and prior studies indicate that as anxiety increases, systolic blood pressure increases.  You predict that taking tests, especially statistics tests, arouses anxiety, and hence systolic blood pressure will increase when taking statistics tests.  Twelve college females enrolled in statistics volunteer to have their systolic blood pressure measured midway through their first statistics test.   Their mid-test blood pressures are presented below. 118,  133,  142,  132,  111,  140,  122,  149,  124,  116,  128,  129Set your alpha level at α = .01.  Complete step 3 of the hypothesis testing procedure and calculate z or t, whichever is appropriate for these data.  Round to the nearest hundredths place.  If your calculated z or t is not identical to one of the values below, but within plus or minus 0.2 of an answer below, assume it’s a rounding error and select the answer that is closest to your calculated value.  Ignore the minus sign if your calculated z or t is negative.

A.  0.82

B.  2.14

C.  1.76

D.  8.67

E. 2.66

F. the correct value of z or t is not listed in alternatives “a” through “e”, even when taking into   consideration a rounding error of plus or minus 0.2.

Question 7

The mean number of close friends for the population freshman college students in the U.S.A. is  µ = 5.7. The standard deviation of scores in this population is σ  = 1.3.  A psychologist predicts that the mean number of close friends for freshman introverts will be significantly different from the mean of the population. The mean number of close friends for a random sample of 25 freshman introverts is M = 6.5.  Set your alpha level at α = .05.  Complete step 3 of the hypothesis testing procedure and calculate z or t,  whichever is appropriate for these data.  Round to the nearest hundredths place.  If your calculated z or t is not identical to one of the values below, but within plus or minus 0.2 of an answer below, assume it’s a rounding error and select the answer that is closest to your calculated value.  Ignore the minus sign if your calculated z or t is negative.

A. .62

B. 2.14

C. 3.08

D. 4.61

E.  16.00

F. the correct value of z or t is not listed in alternatives “a” through “e”, even when taking into   consideration a rounding error of plus or minus 0.2.

Question 8

A researcher knows that the weights of 3-year old children are normally distributed with µ = 40 pounds and ơ = 8. She speculates that children in poverty-stricken regions are undernourished and therefore underweight. With a sample of N = 12 children in a poverty-stricken zone of a large metropolitan city, the researcher obtained the weights of each child. Determine if the weights for this sample are significantly lower than what would be expected for the regular population of 3-year-olds. The weights (in pounds) for this sample are: 48, 45, 42, 37, 29, 33, 35, 39, 24, 32, 40, 42

Which of the following are the correct statements of the null and alternate hypotheses, H0 and HA ?

A.  H0: µ = 40 and HA: µ 40

B.  H0: µ 40 and HA: µ = 40

C. H0: µ > 40 and HA: µ 40

D.  H0: µ 40 and HA: µ < 40

E. H0: µ < 40 and HA: µ 40

F.  H0: µ 40 and HA: µ > 40

Question 9

A researcher knows that the weights of 3-year old children are normally distributed with µ = 40 pounds and ơ = 8. She speculates that children in poverty-stricken regions are undernourished and therefore underweight. With a sample of N = 12 children in a poverty-stricken zone of a large metropolitan city, the researcher obtained the weights of each child. Determine if the weights for this sample are significantly lower than what would be expected for the regular population of 3-year-olds. The weights (in pounds) for this sample are: 48, 45, 42, 37, 29, 33, 35, 39, 24, 32, 40, 42

Complete step 3 of the hypothesis testing procedure and calculate z or t, whichever is appropriate for these data. Round to the nearest hundredths place. If your calculated z or t is not identical to one of the values below, but within plus or minus 0.2 of an answer below, assume it’s a rounding error and select the answer that is closest to your calculated value. Ignore the minus sign if your calculated z or t is negative.

A. 1.23

B.  1.45

C.  1.61

D. 2.08

E. 3.57

F.  the correct value of z or t is not listed in alternatives “a” through “e”, even when taking into consideration a rounding error of plus or minus 0.16.

Question 10

Assume you’re interested in the mental health effects of the “caregivers” caring for the elderly with Alzheimer’s disease.  Specifically, you expect that such caregivers will suffer from significantly elevated levels of depression as compared to the general population.  To measure depression in care-givers, you use a standard test of depression (STD) on which scores range from zero to 40, with high scores indicating higher levels of clinical depression.  The  mean in the general (normal) population of  on this test is µ = 20.  You get permission from ten caregivers who have worked in a local assisted living facility for Alzheimer’s patients for over two years to participate in your study. They are administered the STD and their scores are below.   18,  33,  32,  22,  31,  29,  21,  26,  17,  25With α = .01, determine the critical value of z* or t* that needs to be employed here.  The value of the appropriate of  z* or t* is: A.  2.228

B. 2.58

C. 2.33

D. 2.821

E. 3.169

F. the correct value of z* or t*  is not listed in alternatives “a” through “e”

Question 1 The mean number of close friends for the population freshman college students in the U.S.A. is µ = 5.7. The standard deviation of scores in this population is σ = 1.3. A psychologist