helppp plz I was able to get the first but second one is confusing, please and thank you!

Question

The effectiveness of a blood-pressure drug is being investigated. An experimenter finds that, on average, the reduction in systolic blood pressure is 37 for a sample of size 12 and standard deviation 7.

Estimate how much the drug will lower a typical patient's systolic blood pressure (using a 80% confidence level).

Give your answers to one decimal place and provide the point estimate with its margin of error.

___37_____±____?____

Answer 1

Hi Glitter,

Your point estimate is the sample mean, 37, or 37.0 to one decimal. Formula for margin of error:

MoE = t*SE

t*= t-critical value

SE= standard error

SE = s/sqrt(n)

s= standard deviation = 7

n= sample size = 12

SE= 7/sqrt(12)

SE= 2.0

To get t*, you need the confidence level (80%) and degrees of freedom. Formula for degrees of freedom is:

df = n -1

df = 12 -1 = 11

From t-table, can also use statistical software:

t_{80, 11} = 1.363

So:

MoE = (2.0*1.363)

MoE= 2.8

Final Answer: 37.0 +/- 2.8