Question

The manufacturer of a smart watch claims that individuals who pay attention to how many steps they take per day will inadvertently take more steps per day than individuals who pay no attention to how many steps they take per day. To investigate this claim, the manufacturer conducts a study to estimate the difference in the mean number of steps taken by those that pay attention to how many steps they take per day and those that do not. To do so, 40 volunteers are recruited.

Answer 1

Hello your question is incomplete attached below is the complete question

answer : 1596 ± 2.861
`\sqrt{(1580^2 )/(20 ) +(2350^2 )/(20 ) }` ------ ( A )

Explanation:

I will use excel function to resolve this question

Determine the 99% confidence of interval for the difference in mean number of steps by all people

∝ = 0.01

critical value ( t ) = 2.861 ( = TINV ( 0.01, 19 )

Given that :

S1 = 1580

S2 = 2350

n1 = 20

n2 = 20

Difference in mean = x1 - x2 = 1596

Margin of Error = t *
`\sqrt{(S^2_(1) )/(n_(1) ) +(s^2_(2) )/(n_(2) ) }`

∴ 99% confidence of interval

= 1596 ± 2.861
`\sqrt{(1580^2 )/(20 ) +(2350^2 )/(20 ) }` ------