Question

Test the claim that μ _{1} > μ _{2}. Two
samples are random, independent, and come from populations that are
normally distributed. The sample statistics are given below. Assume
that o1 ≠ o2. Use α = 0.01.

n1=18 n2=13

x1=520 x2=505

s1=40 s2=25

Answer #1

since test statistic does not falls in rejection region we fail to reject null hypothesis |

we do not have have sufficient evidence to conclude that population 1 mean is greater than population 2 |

Confidence Interval for 2-Means (2 Sample T-Interval)
Given two independent random samples with the following
results:
n1=11
n2=17
x1¯=118
x2¯=155
s1=18
s2=13
Use this data to find the 99% confidence interval for the true
difference between the population means. Assume that the population
variances are equal and that the two populations are normally
distributed. Round values to 2 decimal places.
Lower and Upper endpoint?

Exercise 2. The following information is based on independent
random samples taken from two normally distributed populations
having equal variances:
Sample 1
Sample 2
n1= 15
n2= 13
x1= 50
x2= 53
s1= 5
s2= 6
Based on the sample information, determine the 90% confidence
interval estimate for the difference between the two population
means.

Consider the test of the claims that the two samples described
below come from two populations whose means are equal vs. the
alternative that the population means are different. Assume that
the samples are independent simple random samples and that both
populations are approximately normal with equal variances. Use a
significance level of α=0.05 Sample 1: n1=18, x⎯⎯1=28, s1=7 Sample
2: n2=4, x⎯⎯2=30, s2=10
(a) Degrees of freedom =
(b) The test statistic is t =

Consider the following data from two independent samples with
equal population variances. Construct a 90% confidence interval to
estimate the difference in population means. Assume the population
variances are equal and that the populations are normally
distributed.
x1 = 37.1
x2 = 32.2
s1 = 8.9
s2 = 9.1
n1 = 15
n2 = 16

Provided below are summary statistics for independent simple
random samples from two populations. Use the pooled t-test and the
pooled t-interval procedure to conduct the required hypothesis
test and obtain the specified confidence interval.
x1= 19, s1= 3, n1= 12, x2= 15, s2= 2, n2=13
a. What are the correct hypotheses for a left-tailed test?
b. Compute the test statistic.
c. Determine the P-value.
d. The 90% confidence interval is from _____ to _______ ?

The following results are for independent random samples taken
from two populations.
Sample 1
Sample 2
n1 = 40
n2 = 50
x1 = 32.2
x2 = 30.1
s1 = 2.6
s2 = 4.3
(a) What is the point estimate of the difference between the two
population means?
(b) What is the degrees of freedom for the t
distribution?
(c) At 95% confidence, what is the margin of error?
(d) What is the 95% confidence interval for the difference
between...

rovided below are summary statistics for independent simple
random samples from two populations. Use the pooled t-test and the
pooled t-interval procedure to conduct the required hypothesis
test and obtain the specified confidence interval. X1=20, S1=6,
N1=21, X2=22, S2=7, N2= 15 Left tailed test, a=.05 90% confidence
interval The 90% confidence interval is from ____ to ____

Given two independent random samples with the following
results:
n 1 =8x ‾ 1 =89s 1 =19 n1=8x‾1=89s1=19
n 2 =11x ‾ 2 =128s 2
=28 n2=11x‾2=128s2=28
Use this data to find the 90% 90% confidence interval for the
true difference between the population means. Assume that the
population variances are not equal and that the two populations are
normally distributed.
n1 8, n2 11, x1 89, x2 128, s1 19, s2 28
Step 2 of 3 :
Find the margin of error to...

The following results are for independent random samples taken
from two populations.
Sample 1
Sample 2
n1 = 20
n2 = 30
x1 = 22.8
x2 = 20.1
s1 = 2.6
s2 = 4.6
(a)
What is the point estimate of the difference between the two
population means? (Use
x1 − x2.
)
(b)
What is the degrees of freedom for the t distribution?
(Round your answer down to the nearest integer.)
(c)
At 95% confidence, what is the margin...

The following results are for independent random samples taken
from two populations.
Sample 1
Sample 2
n1 = 20
n2 = 30
x1 = 22.5
x2 = 20.1
s1 = 2.2
s2 = 4.6
(a)
What is the point estimate of the difference between the two
population means? (Use
x1 − x2.
)
(b)
What is the degrees of freedom for the t distribution?
(Round your answer down to the nearest integer.)
(c)
At 95% confidence, what is the margin...

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