1. An English teacher has been teaching a sixth grade composition class for many years. He has the feeling that over the past several years, the writing ability of students has changed. A national test of proficiency in composition was administered 5 years ago. The resulting distribution of scores was normally shaped, had a mean of 85 and a standard deviation of 10.9. In order to test his feeling, he gives his present class of 43 students the same proficiency test. The resulting mean is 80. The obtained value of the appropriate statistic for testing H0 is _________.

a.zobt = -0.46

b.zobt = +3.01

c.zobt = -3.01

d.zobt = -0.45

2. An English teacher has been teaching a sixth grade composition class for many years. He has the feeling that over the past several years, the writing ability of students has changed. A national test of proficiency in composition was administered 5 years ago. The resulting distribution of scores was normally shaped, had a mean of 85 and a standard deviation of 10.9. In order to test his feeling, he gives his present class of 43 students the same proficiency test. The resulting mean is 80.Using= .05, 2 tail, the appropriate critical value is _________.

a.zcrit = -1.645

b.zcrit = 1.96

c.zcrit = -1.96

d.zcrit = 1.645

3. An English teacher has been teaching a sixth grade composition class for many years. He has the feeling that over the past several years, the writing ability of students has changed. A national test of proficiency in composition was administered 5 years ago. The resulting distribution of scores was normally shaped, had a mean of 85 and a standard deviation of 10.9. In order to test his feeling, he gives his present class of 43 students the same proficiency test. The resulting mean is 80. What is your conclusion, using alpha = .05 2 tail?

a.reject H0; the present class appears deficient in composition writing

b.retain H0; the present class is not deficient in composition writing

c.accept H0; the present class is not deficient in composition writing

d.reject H0; the present class is not deficient in composition writing

4. A normally distributed set of population scores has a mean of 65 and a standard deviation of 10.2. The mean, of the sampling distribution of the mean, for samples of size 48 equals ______.

a.1.35

b.60

c.65

d.none of the above

5. A normally distributed set of population scores has a mean of 65 and a standard deviation of 10.2. The standard error of the mean for samples of N=25 equals _____.

a.4.8

b.1.47

c.2.04

d.65