11, 12. A statistic is a measure on a sample, while a parameter is a measure on a population.
13. SEm = SD/√n = SEm = 12/√75 = ?
14, 15. Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions/probabilities related to the Z scores.
A standardized third grade reading test, called the We Can Read Test, has a mean of 50 with a standard deviation of 10. A developmental psychologist conducts a study, where he assesses the reading ability of a random sample of 75 third graders using the We Can Read Test, and finds a mean of 53 with a standard deviation of 12.
11. Which of the following is a statistic?
a. 50
b. 53
c. 75
d. 10
12. Which of the following is a parameter?
a. 75
b. 53
c. 10
d. 12
13. What is the measure of spread of the sampling distribution of sample means?
a. 10
b. 12
c. 1.15
d. 1.39
14. What proportion of a normal distribution corresponds to z scores greater than +1.23? a. .8907
b. .3907
c. .6093
d. .1093
15. What is the percentage of observations that fall between az score of -2.3 and +0.70?
a. 74.73
b. 25.80
c. 48.93
d. 75.80
1 answer