Answer:
Belinda's score is 32 strokes.
Step-by-step explanation:
Let the score of John be "x" and Belinda be "y".
It is given that, in the game of golf, John's score was 10 less than two times Belinda's score.
Also, John's score is 54 strokes.
The above equation can be written as ;
Here, x = 54,
Thus, Belinda's score is 32 strokes.
Answer:
Critical value: z = 1.28
The 80% confidence interval for the mean repair cost for the washers is between $46.487 and $82.033.
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of
So it is z with a pvalue of 1-0.1 = 0.9, so z = 1.28
Now, find the margin of error M as such
In which is the standard deviation of the population and n is the size of the sample.
So
The lower end of the interval is the mean subtracted by M. So 64.26 - 17.773 = $46.487.
The upper end of the interval is M added to the mean. So 64.26 + 17.773 = $82.033.
The 80% confidence interval for the mean repair cost for the washers is between $46.487 and $82.033.