A significance test is to be conducted concerning population means and based on the difference between the two sample means . What assumptions are required in order for the two-sample z statistic to be valid

In order for the two-sample z statistic to be valid we need that the following assumptions hold:

each sample and population must be independent from each othereach population must be normally distributedthe population standard deviations must be known or the sample sizes must be ≥ 30samples must be randomdata has to be continuous

The equation will be : 0.8x – 12

Step-by-Step Explanation:

Let the original price of the jacket be = x

As given, the jacket is on sale of $15 off, so the sale price is = x-15

Its also given that as part of a one-day sale, a 20% discount is applied to all purchases which means that after the 20% discount, the final price will be 0.80 times the sale price.

So, the final price of the jacket will be :

= (Though options or equations are not given to choose from, but this is the only correct answer.)