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
Answer:
Yes 20/30 is equivalent to 2/3
Step-by-step explanation:
Divide the fraction 20/30 by 10/10 to simply to 2/3
Answer:
- time: t = -0.3
- minimum: v = 0.55
Step-by-step explanation:
For quadratic ax^2 + bx + c, the extreme value is found at x=-b/(2a). For your quadratic, the minimum is found at ...
t = -(3)/(2(5))
t = -0.3 . . . . . time of minimum velocity
__
The value of velocity at that time is ...
v = 5(-0.3)^2 +3(-0.3) +1 = 5(.09) -.9 +1
v = 0.55 . . . . . value of minimum velocity