Business
Answer:
a.
Obtain the mean and standard deviation using MINITAB procedure.
MINITAB procedure:
Step 1: Choose Stat Basic Statistics Display Descriptive Statistics.
Step 2: In Variables enter the column of Prices.
Step 3: In Statistics , select Mean , StDev and N Number.
Step 4: Click OK.
MINITAB output:
From the MINITAB output, the mean price
is
and the standard deviation
of the prices is
.
Answer:
a.
Obtain the mean percent earnings for the population of jobs by using MINITAB.
MINITAB procedure:
Step 1: Choose Stat Basic Statistics Display Descriptive Statistics.
Step 2: In Variables , enter Earnings.
Step 3: In Statistics , select Mean and StDev.
Step 4: Click OK.
MINITAB output:
From the above MINITAB output, the point estimate mean percent earning
for the population of jobs is
.
b.
Obtain a 95% confidence interval for the mean percent earnings for the population of jobs using a large-sample argument.
The level of significance is 0.95.
From the table B-2, the table value of
is given below:
The general formula for the confidence interval estimate for population mean using large- sample argument is
Obtain standard deviation by using MINITAB.
From the above MINITAB output in part (a), the standard deviation
is
.
The 95% confidence interval is obtained below:
Substitute,
,
,
and
.
Therefore, the 95% confidence interval for mean percent earning for population of jobs lies between
.
c.
Obtain a 95% confidence interval for the mean percent earnings for the population of jobs using a small-sample argument.
From the table B-3, the table value of
with
degrees of freedom is given below:
Thus, the value of
is
.
The 95% confidence interval is obtained below:
Thus, the 95% confidence interval for the mean percent earning for the population of jobs is
. The additional assumption that is made in this case is that the mean percent earnings are approximately normally distributed.
d.
Explanation:
From part (b) and (c), it is clear that the confidence intervals are approximately same. This is because the multipliers 1.96 and 2.045 are almost has the same magnitude.
Answer:
a.
Obtain the point estimate of the mean
.
The sample mean
is the point estimate of the mean
.
Therefore, the point estimate of the mean
is
.
Obtain the 95% error margin.
It is given that 95% confidence interval for the mean profit per transaction is
Therefore, the 95% error margin is
.
b.
Obtain the 90% confidence interval for the mean
.
For, the two-tailed test,
From Table B-2, the required
value for 90% confidence level is,
Thus, the 90% confidence interval is obtained below:
Therefore, the 90% confidence interval for the mean profit per transaction is
.