The awnser is 4.2 I hope this helps
Answer: Student X and Y
Step-by-step explanation:
Student W started off correctly as they simplified the first expression and got rid of the parentheses.
Student Z also started off correctly as they simplified the second expression and combined the like terms.
I don’t see what students X and Y did as their first step but I hope this helps. Sorry if it doesn’t
Original cost -total cost to get amount of tax.
The mean ( average ) is given as 1200 hours.
The standard deviation is 200, sample size is 100.
Find the standard error:
√(200^2 / 100) = 20
Now calculate the confidence interval. For 95% the Z number is 1.96
Multiply Z by the standard error:
1.96 x 20 =39.2
Now find the range that the mean should be within:
1200 - 39.2 = 1160.8
1200 + 39.2 = 1239.2
The samples should be between 1160.8 and 1239.2 for a 95% confidence interval.
Since the average was 1050, which is below 1160.8 the bulbs are not in compliance.
