PSY 87540 Midterm III-Suppose you drew a random sample from a population

1 .  Suppose you drew a random sample from a population where the mean is 100 .  The standard error of the sampling distribution is 10 .  The mean for your sample is 80 . What could you conclude about your sample?
A .  The sample mean does not occur very often by chance in the sampling distribution of means and probably did not come from the given population .
B .  The sample mean occurs very often by chance in the sampling distribution of means and probably did not come from the given population .
C .  The sample mean does not occur very often by chance in the sampling distribution of means but probably did come from the given population .
D .  The sample mean occurs very often by chance in the sampling distribution of means and probably did come from the given population .  

2 .  What do we call that portion of the sampling distribution in which values are considered too unlikely to have occurred by chance?
A .  Region of criterion value
B .  Region of critical value
C .  Region of rejection
D .  Critical value

3 .  Suppose you take a piece of candy out of a jar, look to determine its color, then put it back into the jar before you randomly select the next piece of candy .  This type of sampling is called
A .  an independent event .
B .  sampling with replacement .
C .  a dependent event .
D .  sampling without replacement .  

4 .  There are 26 red cards in a playing deck and 26 black cards .  The probability of randomly selecting a red card or a black card is 26/52 = 0 . 50 .  Suppose you randomly select a card from the deck five times, each time replacing the card and reshuffling before the next pick .  Each of the five selections has resulted in a red card .  On the sixth turn, the probability of getting a black card
A .  has got to be low because you’ve gotten so many red cards on the previous turns .
B .  has got to be high because you’ve gotten so many red cards on the previous turns .
C .  is the same as it has always been if the deck is a fair deck .
D .  needs to be recomputed because you are sampling with replacement .  

5 .  What can you conclude about a sample mean that falls within the region of rejection?
A .  The sample probably represents some population other than the one on which the sampling distribution was based .
B .  The sample represents the population on which the sampling distribution was based .
C .  Another sample needs to be collected .
D .  The sample should have come from the given population .

6 .  What can we conclude when the absolute value of a z-score for a sample mean is larger than the critical value?
A .  The random selection procedure was conducted improperly .
B .  The sample mean is reasonably likely to have come from the given population by random sampling .
C .  The sample mean represents the particular raw score population on which the sampling distribution is based .
D .  The sample mean does not represent the particular raw score population on which the sampling distribution is based .  

7 .  When rolling a pair of fair dice, the probability of rolling a total point value of “7” is 0 . 17 .  If you rolled a pair of dice 1,000 times and the point value of “7” appeared 723 times, what would you probably conclude?

A .  This is not so unlikely as to make you doubt the fairness of the dice .
B .  Although not impossible, this outcome is so unlikely that the fairness of these dice is questionable .
C .  Since the total point value of “7” has the highest probability of any event in the sampling distribution, this is an extremely likely outcome .
D .  It is impossible for this to happen if the dice are fair .  

8 .   What is the appropriate outcome of a z-test?
A . Reject and accept
B . Reject and accept
C . Reject ; accept
D . Fail to reject ; accept

9 .  The null hypothesis describes the
A .  sample statistic and the region of rejection .
B .  sample statistic if a relationship does not exist in the sample .
C .  population parameters represented by the sample data if the predicted relationship exists .
D .  population parameters represented by the sample data if the predicted relationship does not exist .  

10 .  In a one-tailed test, is significant only if it lies
A .  nearer µ than and has a different sign from
B .  in the tail of the distribution beyond and has a different sign from
C .  nearer µ than and has the same sign as
D .  in the tail of the distribution beyond and has the same sign as

11 .  The key difference between parametric and nonparametric procedures is that parametric procedures
A .  do not require that stringent assumptions be met .  

B .  require that certain stringent assumptions be met .
C .  are used for population distributions that are skewed .
D .  are used for population distributions that have nominal scores .  

12 .  Which of the following accurately defines a Type I error?
A . Rejecting when is true
B . Rejecting when is false
C . Retaining when is true
D . Retaining when is false

13 .  If and what is the value of
A . 2 . 58
B . 0 . 52
C . –2 . 58
D .  0 . 78

14 .  What happens to the probability of committing a Type I error if the level of significance is changed from a =0.01 to a =0.05?
A .  The probability of committing a Type I error will decrease .
B .  The probability of committing a Type I error will increase .
C .  The probability of committing a Type I error will remain the same .
D .  The change in probability will depend on your sample size .  

15 .  Suppose you perform a two-tailed significance test on a correlation between the number of books read for enjoyment and the number of credit hours taken, using 32 participants .  Your is –0 . 15, which is not a significant correlation coefficient . Which of the following is the correct way to report this finding?
A .  r(32) = –0 . 15, p > 0 . 05
B .  r(31) = –0 . 15, p > 0 . 05
C .  r(30) = –0 . 15, p < 0 . 05
D .  r(30) = –0 . 15, p > 0 . 05

16 .  Which of the following would increase the power of a significance test for correlation?
A.  Changing a from 0 . 05 to 0 . 01
B. Increasing the variability in the Y scores
C. Changing the sample size from N = 25 to N = 100
D. Changing the sample size from N = 100 to N = 25

17 .  If a sample mean has a value equal to µ, the corresponding value of t will be equal to
A .  +1 . 0 .
B .  0 . 0 .
C .  â€“1 . 0 .
D .  +2 . 0 .  

18 .  What is ?
A .  The estimated population standard deviation
B .  The population standard deviation
C .  The estimated standard error of the mean
D .  The standard error of the mean

19 .  In a one-tailed significance test for a correlation predicted to be positive, the null
hypothesis is ___________ and the alternative hypothesis is __________ .
A. Ho: ρ ≤ 0; Ha: ρ > 0
B. Ho: ρ < 0; Ha: ρ ≥ 0
C. Ho: ρ = 0; Ha: ρ > 0
D. Ho: ρ < 0; Ha ρ > 0

20 .  How is the t-test for related samples performed?
A .  By conducting a one-sample t-test on the sample of difference scores
B .  By conducting an independent samples t-test on the sample of difference scores
C .  By converting the scores to standard scores and then performing a related samples t-test
D .  By measuring the population variance and testing it using an independent samples t-test

21 .  What does the alternative hypothesis state in a two-tailed independent samples
experiment?

Ho: mu1-mu2=0
22 .  One way to increase power is to maximize the difference produced by the two conditions in the experiment .  How is this accomplished?
A .  Change a from 0 . 05 to 0 . 01 .
B .  Change the size of N from 100 to 25 .
C .  Design and conduct the experiment so that all the subjects in a sample are treated in a consistent manner .
D .  Select two very different levels of the independent variable that are likely to produce a relatively large difference between the means .  

23 .  Suppose you perform a two-tailed independent samples t-test, using a = 0 . 05, with 15 participants in one group and 16 participants in the other group .  Your is 4 . 56, which is significant .  Which of the following is the correct way to report this finding?
A .  t(31) = 4 . 56; p< 0 . 05
B .  t(29) = 4 . 56; p < 0 . 05
C .  t(29) = 4 . 56; p > 0 . 05
D .  t(29) = 4 . 56; p = 0 . 05

24 .  Suppose that you measure the IQ of 14 subjects with short index fingers and the IQ
of 14 subjects with long index fingers .  You compute an independent samples t-test,
and the is 0 . 29, which is not statistically significant .  Which of the following is the
most appropriate conclusion?
A .  There is no relationship between length of index finger and IQ .
B .  There is a relationship between length of index finger and IQ .
C .  The relationship between length of index finger and IQ does not exist .
D .  We do not have convincing evidence that our measured relationship between length of index finger and IQ is due to anything other than sampling error .  

25 .  The assumptions of the t-test for related samples are the same as those for the test for independent samples except for requiring
A .  that the dependent variable be measured on an interval or ratio scale .
B .  that the population represented by either sample form a normal distribution .
C .  homogeneity of variance .
D .  that each score in one sample be paired with a particular score in the other sample .  

Use SPSS and the provided data set to answer the questions below:
26 .  Test the age of the participants (AGE1) against the null hypothesis H 0 = 34 .  Use a
one-sample t-test .  How would you report the results?
A .  t = -1 . 862, df = 399, p > . 05
B .  t = -1 . 862, df = 399, p < . 05
C .  t = 1 . 645, df = 399, p > . 05
D .  t = 1 . 645, df = 399, p < . 05

27 .  Test to see if there is a significant difference between the age of the participant and the age of the partner .  Use a paired-sample t-test and an alpha level of 1% .  How would you interpret the results of this test?
A .  The partners are significantly older than the participants .
B .  The partners are significantly younger than the participants
C .  The age of the participants and partners are not significantly different .
D .  Sometimes the partners are older, sometimes the participants are older .  

28 .  Look at the correlation between Risk-Taking (R) and Relationship Happiness (HAPPY) .  Use the standard alpha level of 5% .  How would you describe the relationship?
A .  The relationship is non-significant .
B .  There is a significant negative relationship .
C .  There is a significant positive relationship .
D .  The correlation is zero .  

29 .  If you randomly chose someone from this sample, what is the chance that they
described their relationship as either Happy or Very Happy?
A .  32%
B .  37%
C .  56%
D .  69% 

30 .  Perform independent sample t-tests on the Lifestyle, Dependency, and Risk-Taking
scores (L, D, and R) comparing men and women (GENDER1) .  Use p &lt;  . 05 as your
alpha level .  On each of the three scales, do men or women have a significantly
higher score?
A .  Lifestyle: Men, Dependency: Women, Risk-Taking: Men .
B .  Lifestyle: Not significantly different, Dependency: Women, Risk-Taking: Men
C .  Lifestyle: Women, Dependency: Women, Risk-Taking: Men
D .  Lifestyle: Men, Dependency: Men, Risk-Taking: Not significantly different