PSYCH STATS T/F- Chapter 4 and 5

8.) The characteristics of the sampling distribution of the mean are described by the Central Distribution Theorem.

False

9.) The sampling distribution of the mean will be normally distributed only if sample sizes are are relatively small.

False

5. The distribution of scores on the first test in your statistics class is an example of an empirical distribution

True

5.) In sampling with replacement, each case that is selected for inclusion in a sample is put back into the population and potentially can be selected again for inclusion in the same sample.

True

7. The majority of cases in a normal distribution fall between one standard deviation below and one standard deviation above the mean

True

7.) In constructing a sampling distribution of the mean, each sample drawn from the population must be of the same size

True

8. The mean on a test is 75 and the standard deviation is 10. If the scores are normally distributed we know that most of the scores fall between 65 and 85

True

9. The mean on a test is 60 and the standard deviation is 15.Assuming that the distribution is normal the probability of randomly drawing a score between 60 and 75 is 34.13% or .3413

True

6.) In a population of 5 cases , there are 25 different samples of size N= 2 when we sample with replacement

False

40. The z-score marking the 75th percentile is + .67

True

6. All distributions that are bell-shaped and symmetrical are normal distributions

False

1. The normal distribution is referred to as an empirical distribution.

False

10. The mean on a test is 70 and the standard deviation is 8. Assuming the distribution is normal, the probability of randomly drawing a score between 54 and 62 is 2.14% or .0214

False

10.) The Sampling distribution of the mean will be normally distributed only if samples are relatively large and the population is normally distributed

False

11. There are 14 freshman , 12 sophomore, 14 juniors, and 8 seniors in a class . The probability of drawing a senior at randoms is 8% or .08

False

13. Being male and being a college student are mutually exclusive events.

False

16. The age of a man and the age of his wife are independent events.

False

17. The probability that a score drawn at random from a normal distribution will not fall between the mean and one standard deviation above the mean is .3413.

False

19. The probability of rolling a single die and getting either a 2 or a 4 is .03.

False

2.)A sampling distribution is called theoretical because it is impossible to actually construct one.

False

21. The probability of rolling two dice and getting a 2 and a 4 is .33

False

25. There is no such thing as a z-score higher than +4 or lower than -4.

False

26. One way to change a skewed distribution into a normal distribution is to standardize the scores

False

30. Percentile Ranks provide an interval scales of measurement while z-scores provide only and ordinal scale

False

31. The mean on psychology test was a 75 and the standard deviation was 10. The mean on the sociology test was 7 with a standard deviation of 2 John took both test and scored 85 and 9. We can conclude that he scored higher on the sociology test.

False

33. The proportion of the area under the curve that falls above a z-score of -1 is .1587

False

36. We estimate a scores percentile rank by finding the proportion of the are above that score in the standard normal distribution

False

37. In a normal distribution of scholastic motivation scores having a mean of 100 and standard deviation of 20, the percentile rank of a score of 70 is 43.32%.

False

4.) In constructing a sampling distribution, we use sampling without replacement.

False

1.) If you drew all possible samples of size N from a population, computed the median for each sample, and plotted the frequency with which the various values occurred, you would have the sampling distribution of the median

True

12. There are 29 males and 13 females in a class. The probability of drawing a male at random is 69% or .69

True

14. Being married and being single are mutually exclusive events.

True

15. The results of rolling two dice are independent events.

True

18.The probability that a score drawn at random from a normal distribution will not fall between one standard deviation below and one standard deviation above the mean is .3174.

True

2. A theoretical distribution is one that is only imaginary.

True

20. The probability that a score drawn at random from a normal distribution falls higher than 2 standard deviations above the mean or lower than 2 standard deviations below the mean is 4.56 or .0456.

True

22. The probability that two scores drawn from a normal distribution will both fall between one standard deviation below and one standard deviation above the mean is .4659

True

23. In a distribution having a mean of 75 and standard deviation of 10, the z-score at the mean is 0.

True

24. In any distribution will always equal of z-scores, the standard deviation will always equal 1.

True

27. Transforming raw scores to z-scores has no affect on the shape of the distribution

True

28. Transforming raw scores to z-scores always produces a mean of 0 and a variance of 1

True

29. Percentile ranks and z-scores both provide a way of locating scores in a distribution

True

3. Real scores are never normally distributed.

True

3.) It is unnecessary to construct sampling distributions because we know their essential characteristics without constructing them

True

32. The mean on the test of scholastic aptitude is 500 with a standard deviation of 100. The mean on the test of scholastic motivation is test is 100 with a standard deviation of 20. John's scholastic aptitude test score is 600 and his scholastic motivation score is 115. We can conclude that John has more scholastic aptitude than scholastic motivation.

True

34. The higher probability of randomly drawing a z-score of .33 or higher from the standard normal distribution is .3707

True

35. In a normal distribution of scholastic aptitude scores having a mean of 500 and standard deviation of 100, the probability of drawing two cases which both score 600 or higher is .0252

True

38. In a normal distribution, approximately 62.47% of the cases fall between z-scores of -1.5 and +.5.

True

39. The z-score marking the 33rd percentile is -.44.

True

4. Many variables show approximately normal distributions.

True