Question
In: Math
A researcher wants to estimate the difference in the means of two populations. A random sample...
A researcher wants to estimate the difference in the means of two populations. A random sample of 36 items from the first population results in a sample mean of 430. A random sample of 49 items from the second population results in a sample mean of 460. The population standard deviations are 120 for the first population and 140 for the second population. From this information, a 95% confidence interval for the difference between means of the first population and the second population is _______. Select one: a. -102.83 to 42.43 b. -87.60 to 27.60 c. -76.53 to 16.53 d. -95.90 to 35.90
Solutions
Expert Solution
Given:
n1=36 ,
The 95%confidence interval for the difference of two population meanis given by:
where
Therefore 95% confidence interval becomes
Hence the 95% confidence interval is:
Therefore b) is the correct choice.
milcah answered 2 months agoRelated Solutions
A researcher wants to estimate the difference in the means of two populations. A random sample...
A researcher wants to estimate the difference in the means of
two populations. A random sample of 36 items from the first
population results in a sample mean of 430. A random sample of 49
items from the second population results in a sample mean of 460.
The population standard deviations are 120 for the first population
and 140 for the second population. From this information, a 95%
confidence interval for the difference in population means is
_______.
Select one:...
In constructing 95% confidence interval estimate for the difference between the means of two populations, where...
In constructing 95% confidence interval estimate for the
difference between the means of two populations, where the unknown
population variances are assumed not to be equal, summary
statistics computed from two independent samples are:
?1=45,?̅1=756,?1=18,?2=40,?̅2=762,?2=15
(using 2-sample T menu)
a. Calculate the 95% confidence interval for the true difference
of two means.
b. Base on the interval in the previous question, can one
conclude there is a difference in means of two populations?
Justify your answer.
Independent random samples selected from two normal populations produced the sample means and standard deviations shown...
Independent random samples selected from two normal populations
produced the sample means and standard deviations shown to the
right.
a.
Assuming equal variances, conduct the test
Upper H 0 : left parenthesis mu 1 minus mu 2 right parenthesis
equals 0H0: μ1−μ2=0
against
Upper H Subscript a Baseline : left parenthesis mu 1 minus mu 2
right parenthesis not equals 0Ha: μ1−μ2≠0
using alpha equals 0.10 .α=0.10.
b.
Find and interpret the
9090%
confidence interval for
left parenthesis mu 1...
independent random samples selected from two normal populations produced the following sample means and standard deviations....
independent random samples selected from two normal populations
produced the following sample means and standard deviations. sample
1: n1= 17, x1= 5.4, s1= 3.4
sample 2: n2 =12, x2 = 7.9, s2= 4.8
a. assuming equal variances, conduct the test ho: (m1-m2) is
equal to 0, against the ha: (m1-m2) isn't equal to 0 using alpha =
.05
b. find and interpret the 95% confidence interval (m1-m2).
Independent random samples selected from two normal populations produced the following sample means and standard deviations....
Independent random samples selected from two normal populations
produced the following sample means and standard deviations.
Sample 1
Sample 2
n1 = 14
n2 = 11
1 = 7.1
2 = 8.4
s1 = 2.3
s2 = 2.9
Find and interpret the 95% confidence interval
for
In testing the difference between the means of two normally distributed populations, if μ1 = μ2...
In testing the difference between the means of two normally
distributed populations, if μ1 =
μ2 = 50, n1 = 9, and
n2 = 13, the degrees of freedom for the
t statistic equals ___________.
19,20,21,22
When comparing two independent population means by using samples
selected from two independent, normally distributed populations
with equal variances, the correct test statistic to use is
______.
z,F,t, t^2
When testing a hypothesis about the mean of a population of
paired differences in which...
A business researcher wants to estimate the average travel time to work in Cleveland. A random...
A business researcher wants to estimate the average travel time
to work in Cleveland. A random sample of 45 Cleveland commuters is
taken and the travel time (in minutes) to work is obtained from
each. The data is shown in the table below.
27
25
19
21
24
27
29
34
18
29
16
28
20
32
27
28
22
20
14
15
29
28
29
33
16
29
28
28
27
23
27
20
27
25
21
18
26...
In order to compare the means of two populations, independent random samples of 400 observations are...
In order to compare the means of two populations, independent
random samples of 400 observations are selected from each
population with the following results:
Sample 1
Sample 2
Sample Mean = 5275
Sample Mean = 5240
s1 = 150
s2 = 200
To test the null hypothesis H0: µ1 -
µ2 = 0 versus the alternative hypothesis Ha:
µ1 - µ2 ╪ 0 versus the alternative hypothesis
at the 0.05 level of significance, the most accurate statement
is:
In order to compare the means of two populations, independent random samples of 424 observations are...
In order to compare the means of two populations, independent
random samples of 424 observations are selected from each
population, with the following results:
Sample 1
Sample 2
x¯1=5169
x¯2=5417
s1=135
s2=130
Use a 96% confidence interval to estimate the difference between
the population means (μ1−μ2).
? ≤(μ1−μ2)≤ ?
Test the null hypothesis: H0:(μ1−μ2)=0 versus the alternative
hypothesis: Ha:(μ1−μ2)≠0. Using α=0.04, give the following:
the test statistic z =
postive critical z score =
negative critical z score =
The...
1) In order to compare the means of two populations, random samples of 105 observations are...
1) In order to compare the means of two populations, random
samples of 105 observations are selected from each population with
the following results: Sample 1 Sample 2 x1 = 258 x2 = 281 s1 =
17.2 s2 = 21.2
Test the null hypothesis H0: (μ1 - μ2 ) = 0 against the
alternative hypothesis H1: (μ1 - μ2 ) ≠ 0 using α = .1 Use the
testing method of your choice. Indicate what operation that you ran
in...
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