Answer: -1.33 .
Step-by-step explanation:
Formula to find the Z-score :

Given: Mean = 191 and Standard deviation = 21
Then , the z-score corresponding to the expected value of 163 will be :

Hence, the z score corresponding to selling 163 inhalers is -1.33 .
Answer:
The selling price is $46 approx.
Step-by-step explanation:
The cost price is = $35.87
Markup is 22% of selling price.
Let the selling price be = 100%
So, 100%-22%=78% = 0.78
So, solution is =
≈ $46.
Hence, the selling price is $46 approx.
Answer:
Margin of error of 0.0485 hours.
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
.
That is z with a pvalue of
, so Z = 1.96.
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.
In this question:

The margin of error is of:



Margin of error of 0.0485 hours.
Answer: 5
Step-by-step explanation:
Let the number = x.
4x + 9x = 65
13x = 65
x = 5