# Project #35455 - statistics

I would like clear solutions on how to solve the following problems, and answers.

Question 1

A psychologist examined the effect of chronic alcohol abuse on memory. In this experiment a standardized memory test was used. Scores for the general population on this test form a normal distribution with μ = 48.00 and population standard deviation σ = 8.00. A sample of n = 45 alcohol abusers has a mean score of M = 42.00. Is there evidence for memory impariment among alcoholics? Use an alpha level of .01 for a one-tail test. (NOTE: Questions 1a-1h are for this question)â€¨What is the null hypothesis?

 a. μ ≠ 48.00 b. μ <  48.00 c. μ = 48.00 d. μ >  48.00

Question 2

What is the alternative hypothesis (H1)?

 a. μ = 48.00 b. μ > 48.00 c. μ < 48.00 d. μ ≠ 48.00

Question 3

.    What is the critical value?â€¨â€¨

 . .    a. .    z critical = -2.33â€¨ . .    b. .    z critical = 2.33â€¨ . .    c. .    z critical = + 2.58â€¨ . .    d. .    z critical = + 1.96â€¨

Question 4

.    standard error of the mean (σm) = ?â€¨â€¨

 a. 5.63 b. 1.19 c. 0.18 d. 0.42

Question 5

z = ?

 a. z = -1.07 b. z = -5.04 c. z = 1.07 d. z = 5.04

Question 6

What is the correct decision regarding this hypothesis test?

 a. Reject Ho, z = 5.04, p < .01 b. Reject Ho, z = -5.04, p < .01 c. Fail to Reject Ho, z = 1.07, p > .01 d. Fail to Reject Ho, z = -1.07, p > .01

Question 7

Calculate the effect size. d = ?

Size of effect (small, medium, or large)?

Question 8

Describe the results in plain English and include a description of the 90% confidence interval.

Question 9

For a normal population with μ = 83.00 and standard deviation σ = 16.00, what is the probability of obtaining a sample mean of M > 76.00.â€¨a. For a random sample of n = 4 scores?â€¨

σm  =

z =

â€¨â€¨proportion/probability =

b. For a random sample of n = 16 scores?â€¨

σm  =

â€¨â€¨z =

proportion/probability =

c. For a random sample of n = 32 scores?â€¨

σm  =

â€¨â€¨z =

proportion/probability =

Question 10

A college professor has noted that this year's freshmen class appears to be smarter than classes from previous years. The professor obtains a sample of n=48 freshmen and computes an average IQ of M = 112.68 with a sample variance (s2) = 285.36 for this group. College records indicate that the mean IQ for entering freshmen from earlier years is μ = 106.32. On the basis of the sample data, can the professor conclude that this year's students have IQs that are significantly different from those of previous students? Use a two-tailed test with an alpha level = .05. (NOTE: Questions 3a-3h are for this question)â€¨What is the null hypothesis?

 a. μ ≠ 112.68 b. μ ≠ 106.32 c. μ = 112.68 d. μ = 106.32

Question 11

What is the alternative hypothesis?

 a. μ = 106.32 b. μ ≠ 112.68 c. μ ≠ 106.32 d. μ = 112.68

Question 12

What is the critical value = ?

 a. + 1.684 b. + 1.96 c. + 2.021 d. +  2.33

Question 13

standard error (sm) = ?

 a. 5.95 b. 41.19 c. 2.84 d. 2.44

Question 14

.    Calculated t = ?â€¨â€¨

 a. 2.607 b. 1.069 c. 2.239 d. 0.154

Question 15

What is the decision?

 a. Fail to Reject Ho, t(47) = 0.154, p > .05 b. Reject Ho, t(47) = 2.239, p < .05 c. Fail to Reject Ho, t(47) = 1.069, p > .05 d. Reject Ho, t(47) = 2.607, p < .05

Question 16

Calculate the effect size. d = ?

Size of effect (small, medium, or large)?

Question 17

Describe the results in plain English and include a description of the 80% confidence interval.

 Subject Mathematics Due By (Pacific Time) 07/16/2014 03:00 pm
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