A survey of several 9 to 11 year olds recorded the following amounts spent on a trip to the mall: $23.71,$17.79,$29.87,$18.78,$28.76 Construct the 95% confidence interval for the average amount spent by 9 to 11 year olds on a trip to the mall. Assume the population is approximately normal. Step 3 of 4 : Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.

(16.904 ; 30.660)

Step-by-step explanation:

Given the data :

X = 23.71,17.79,29.87,18.78,28.76

Sample size = 5

Mean = (23.71+17.79+29.87+18.78,+28.76) / 5 = 23.782

Using a calculator, sample standard deviation :

Standard deviation, s = 5.54

Tcritical at α = 0.05, df = 5 - 1 = 4

Using tables ; Tcritical value = 2.7763

Confidence interval :

Mean ± Margin of Error

Margin of Error (MOE) = Tcritical * SE

Margin of Error = Tcritical * s/sqrt (n)

MOE = 2.7763 * 5.54/Sqrt(5) = 6.878

Confidence interval : 23.782 ± 6.878

Lower boundary : 23.782 - 6.878 = 16.904

Upper boundary = 23.782 + 6.878 = 30.66

(16.904 ; 30.660)

7

step-by-step explanation:

the answer would be 7

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have