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)
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?



. 

.    a.

.    z critical = -2.33


. 

.    b.

.    z critical = 2.33


. 

.    c.

.    z critical = + 2.58


. 

.    d.

.    z critical = + 1.96


Question 4

.    standard error of the mean (σm) = ?



 

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.
a. For a random sample of n = 4 scores?


σm  =

z =



proportion/probability =

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


σm  =



z =

proportion/probability =

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


σm  =



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)
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 = ?



 

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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