Confidence Interval using the t or z test with assumptions

IQ comparison of older vs. younger workers.

the 1967 Age Discrimination in Employment Act made it illegal to discriminate against workers 40 years of age and older. Opponents of the law argue that there are sound economic reasons why employers would not wan tto hire and train workers who are very close to retirement. They also argue that people's abilities begin to deteriorate with age. In fact, Forbe's (Dec 13, 1999) reported that 25-year-olds did significantly better than 60 year olds on the Wechsler Adult Intelligence Scale, the most populat IQ test. The following data are raw test scores (ie, not the familiarized IQ scores) for a sample of thirty six 25-year-olds and 36 60-year-olds:

a) Estimate the mean raw test score for all 25-year-olds using a 99% confidence interval. Give a practical interpretation of the confidence interval.

b) What assumption(s) must hold for the method of estimation used in part a to be appropriate?

c) Find a 95% confidence interval for the mean raw score of all 60-year-olds and interpret your result

This solution is comprised of a detailed explanation of Confidence Interval with the help of excel. In this solution, step-by-step explanation of this complicated topic provides students with a clear perspective of Confidence Interval using the t or z test after discussing the assumptions of the test.

Compute a 95% confidenceinterval for the population mean, based on the sample 1.5, 1.54, 1.55, 0.09, 0.08, 1.55, 0.07, 0.99, 0.98, 1.12, 1.13, 1.00, 1.56, and 1.53. Change the last number from 1.53 to 50 and recalculate to theconfidenceinterval. Usingthe results, describe the effect of an outlier or extreme value on the conf

Try out some of your own ideas for analyzing
this data. Use one of the following techniques:
regression line and equation; correlation
one-sample t-test
one-sample t confidenceinterval
matched-pairs t-test
two-sample t-test
two-sample t confidenceinterval
F-test for variances
ANOVA
one-sample z test for proportions

Assume that in a hypothesis testwith null hypothesis = 13.0 at 0.05, that a value of 11.0 for the sample mean results in the null hypothesis not being rejected. That corresponds to a confidenceinterval result of
A. The 95% confidenceinterval for the mean does not contain the value 13.0
B. The 95% confidenceinterval for

Assume that in a hypothesis testwith null hypothesis H 0: mu = 14.0 at alpha = 0.05, that a value of 13.0 for the sample mean results in the null hypothesis being rejected. That corresponds to a confidenceinterval result of:
a) the 95% confidenceinterval for the mean contains the value 14.0
b) the 95% confidenceinterval

What is the relationship between a confidenceinterval and a single sample, two-tailed hypothesis test?
How are they the same? How are they different?
Review the definition of a single sample, two tailed test. Now review the structure of a confidenceinterval.
What are theassumptions and requirements for the use

Which of the following is not needed to be known to calculate a confidenceinterval?
a. standard deviation
b. sample size
c. mean
d. degree of confidence

Please help withthe following problem.
Usingthe data on the table below, are there any correlations between population changes for the areas listed.
The following is a list of acceptable tests:
regression line and equation; correlation
one-sample t-test
one-sample t confidenceinterval
matched-pairs t-test
two-sa

Usingthe attached Excel file, calculate both a confidenceinterval for a mean (do not worry about the rounding) and a 1-sample t-test that the mean age is less than 62.
What is found? What is the CI and can we reject or accept the null or alternative hypotheses?

A company has 1.100 inventory items. In a sample of 120 items, the historical cost of each item was compared withthe audited value, and 10 items differed in their historical costs and audited values. These values are shown below. Construct a 99% confidenceinterval estimate of total population difference in the historical cost