Referring to question 29,how high must N be to be able to detect a real = 53 with a power of 0.8000?
a. 158 c. 173
b. 222 d. 248
Referring to question 29, if N is increased to 90, power = _________ to detect a real effect such that real = 53.
a. 0.8524 c. 0.4761
b. 0.9103 d. 0.5142
Referring to question 29, the probability of making a Type II error is _________.
a. 0.7764 c. 0.2236
b. 0.2400 d. 0.6459
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 and the standard deviation is 8.7 . Using the z test with = 0.052 tail, what is your conclusion?
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
If we take all possible samples from a normally distributed population, which of the following sample sizes will yield the smallest variation in the means of the samples?
a. 1
b. 85
c. 120
d. 5
e. 15
The sampling distribution of the mean _________.
a. is always normally distributed
b. is normally distributed if the population raw scores are normally distributed
c. is considered normally distributed if N > 300
d. is normally distributed if the population raw scores are normally distributed and is considered normally distributed if N > 300
The normal deviate test is used with _________.
a. a replicated measures design c. a single sample design
b. an independent groups design d. a multi-group design
If the variability of the raw score population increases and N is held constant, _________.
a. decreases c. stays the same
b. increases d. need more information
The mean attention span for adults in a certain village is 15 minutes with a standard deviation of 6.4 . What is the probability of randomly selecting a sample of 30 scores from this population that has a mean attention span equal to or greater than 17 minutes?
a. 0.3783 c. 0.0446
b. 0.0436 d. 0.4564
The mean attention span for adults in a certain village is 15 minutes with a standard deviation of 6.4 . If the means of all possible samples of size 30 is taken from this population, will equal _________.
a. 3.0 c. 0.21
b. 6.4 d. 1.17
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