The formula for this type of question is z=x-u/y
z=-2 (z-value)
u = 27 (mean)
y = 4 (standard deviation)
Therefore -2=x-27/4
You now figure this out like a normal equation
4x-2=4 X x-27/4
-8+27= x-27+27
19=x
Therefore the data value of x is 19
If I read your post properly, the two fractions are -14/10 and -12/b.
The LCD is found by finding prime factors of each term, then collecting the ones that appear the most.
10 = 2 x 5
b = b
2 x 5 x b = 10b
It's easy to look it up in your phone
Considering the situation described, the hypothesis tested are given as follows:
- The null hypothesis is

- The alternative hypothesis is

<h3>What are the hypothesis tested?</h3>
At the null hypothesis, it is tested if the standard deviation is not less than $23, that is:

At the alternative hypothesis, it is tested if there is significant evidence t conclude that the standard deviation is less than $23, that is:

More can be learned about an hypothesis test at brainly.com/question/26454209