Answer:
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Step-by-step explanation:









Answer:
The critical value is T = 1.895.
The 90% confidence interval for the mean repair cost for the washers is between $48.159 and $72.761
Step-by-step explanation:
We have the standard deviation for the sample, so we use the t-distribution.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 8 - 1 = 6
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 6 degrees of freedom(y-axis) and a confidence level of
. So we have T = 1.895, which is the critical value.
The margin of error is:

In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 60.46 - 12.301 = $48.159
The upper end of the interval is the sample mean added to M. So it is 60.46 + 12.301 = $72.761
The 90% confidence interval for the mean repair cost for the washers is between $48.159 and $72.761
Correct, because the area of a square = side x side = side^2
Answer:
Step-by-step explanation:
H0 : μ = 46300
H1 : μ > 46300
α = 0.05
df = n - 1 = 45 - 1 = 44
Critical value for a one tailed t-test(since population standard deviation is not given).
Tcritical = 1.30
The test statistic :(xbar - μ) ÷ (s/sqrt(n))
The test statistic, t= (47800-46300) ÷ (5600√45)
t = 1500
t = 1500 / 834.79871
t = 1.797
The decision region :
Reject H0: if t value > critical value
1. 797 > 1.30
Tvalue > critical value ; We reject H0
Hence, there is sufficient evidence to conclude that cost has increased.
Answer:
28 Nickels
Step-by-step explanation: