Question

1. In a random sample of 58 people aged 20-24, 22.7% were
smokers. In a random sample of 110 people aged 25-29, 29.5% were
smokers. Calculate the margin of error for a 95% confidence
interval that can be used to estimate the difference between the
population proportions p_{1} − p_{2} of the smokers
in these age groups.

**Show your answer in decimal form, rounded to three
decimal places.**

**2. Confidence interval for the difference between
population proportions.**

(Assume that the samples are randomly selected and
independent.)

Sample statistics: x _{1} = 36, n _{1} = 64 and x
_{2} = 47, n _{2} = 71;

Construct a 95% confidence interval for the difference between
population proportions p_{1} – p_{2}

Select one:

a. 0.368 < p_{1} – p_{2} < 0.757

b. -0.263 < p_{1} – p_{2} <
0.064

c. -0.294 < p_{1} – p_{2} < 0.757

d. 0.399 < p_{1} – p_{2} <
0.726

3. As a result of running a simple regression on a data set, the following estimated regression equation was obtained:

** = 9.7 +
13.4 x**

Furthermore, it is known that SST = 622, and SSE = 150.

**Calculate the correlation coefficient R; round
your answer to three decimal places**

Answer #1

(Assume that the samples are randomly selected and
independent.)
Sample statistics: x 1 = 36, n 1 = 64 and x 2 = 47, n 2
= 71;
Construct a 95% confidence interval for the difference
between population proportions p1 – p2
Select one:
0.368 < p1 – p2 < 0.757
-0.263 < p1 – p2 < 0.064
-0.294 < p1 – p2 < 0.757
0.399 < p1 – p2 < 0.726
2.
Two independent samples are randomly selected and...

In a random sample of 500 people aged 20-24, 22% were smokers.
In a random sample of 450 people aged 25-29, 14% were smokers.
Construct a 95% confidence interval for the difference between the
proportions of 20-24 year olds and 25-29 year olds who are smokers.
Also, find the margin of error. What is the Parameter of interest?
What is the underlying Distribution?

5. In a random sample of 500 people in their 30's, 22% were
smokers. In a random sample of 450 people in their 20's, 14% were
smokers. The 95% confidence interval for the difference between the
population proportions P20's - P30's. turned out to be:
-0.128 < p1 - p2 < -0.032. What does this imply?
There is not a significant difference between the smoking habits
of people in their 20's and people in their 30's, but the sample
showed...

Consider the following results for independent samples taken
from two populations.
Sample 1
Sample 2
n1 = 400
n2 = 300
p1 = 0.53
p2 = 0.36
A. What is the point estimate of the difference between the two
population proportions? (Use
p1 − p2.
)
B. Develop a 90% confidence interval for the difference between
the two population proportions. (Use
p1 − p2.
Round your answer to four decimal places.)
to
C. Develop a 95% confidence interval for the...

Consider the following results for independent samples taken
from two populations.
Sample 1
Sample 2
n1 = 400
n2 = 300
p1 = 0.53
p2 = 0.31
(a)
What is the point estimate of the difference between the two
population proportions? (Use
p1 − p2.
)
(b)
Develop a 90% confidence interval for the difference between the
two population proportions. (Use
p1 − p2.
Round your answer to four decimal places.)
to
(c)
Develop a 95% confidence interval for the...

A random sample of 100 traditional aged college students were
asked whether they
would turn to their father or mother for advise if they had a
personal problem. A second
sample of 100 different traditional aged college students was asked
the same question
regarding an academic issue. If 47 of the students in the first
sample and 56 of the
students in the second sample replied that they turned to their
mother rather than their
father for help, test the...

Consider the following results for independent samples taken
from two populations.
Sample 1
Sample 2
n1 = 500
n2= 200
p1= 0.45
p2= 0.34
a. What is the point estimate of the difference
between the two population proportions (to 2 decimals)?
b. Develop a 90% confidence interval for the
difference between the two population proportions (to 4 decimals).
Use z-table.
to
c. Develop a 95% confidence interval for the
difference between the two population proportions (to 4 decimals).
Use z-table....

Consider the following results for independent samples taken
from two populations.
Sample 1
Sample 2
n1 = 500
n2= 300
p1= 0.43
p2= 0.36
a. What is the point estimate of the difference
between the two population proportions (to 2 decimals)?
b. Develop a 90% confidence interval for the
difference between the two population proportions (to 4 decimals).
Use z-table.
to
c. Develop a 95% confidence interval for the
difference between the two population proportions (to 4 decimals).
Use z-table....

Consider the following results for independent samples taken
from two populations.
Sample 1
Sample 2
n1 = 500
n2= 200
p1= 0.46
p2= 0.31
b. Develop a 90% confidence interval for the
difference between the two population proportions (to 4 decimals).
Use z-table.
______ to ________
c. Develop a 95% confidence interval for the
difference between the two population proportions (to 4 decimals).
Use z-table.
________ to _________

In
a random sample of 23 people aged 18-24, the mean amount of time
spent using the internet is 45.1 hours per month with a standard
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1. if one were to calculate a confidence interval for the
population mean, would it be a z or t confidence interval? use the
flow chart to explain your answer.
2....

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