Answer:
Margin of error =z-score value for chosen confidence level×population standard deviation
Assuming a 95% confidence level , then
z=1.96
standard deviation=5.75
Margin of error= 1.96×5.75=11.27
<u>Answer</u>: No, we do not have sufficient evidence to conclude that the mean call duration, µ, is different from the 2010 mean of 9.4 minutes.
Step-by-step explanation:
As per given , we have
, since
is two-tailed so , the test is a two tail test.
Since population standard deviation is unknown, so we use t-test.
Critical value (two-tailed) for significance level of 0.01=
For n =50 ,
and s= 4.8
Test statistic : 

Since test statistic value (-1.18) lies in critical interval (-2.609228, 2.609228), it means the null hypothesis is failed to reject.
We do not have sufficient evidence to conclude that the mean call duration, µ, is different from the 2010 mean of 9.4 minutes.
Answer:
C
Step-by-step explanation:
The angle is total is 138 degrees. Part of the entire angle is already given (the 88 degree measure), so all you have to do is subtract 88 from 138, which is 50.
3*60 = 180 minutes
80/180 = 0.44
1-0.44 = 0.56
it was a 56% decrease in commute time
Answer:
y = 10
Step-by-step explanation:
4/5 y = 8
4/5 y * 5/4 = 8 * 5/4 multiply by reciprocal
y = 10