Question

(statistics)PLS help ive been looking at similar questions all night. i need tan explanation of how to solve using a ti-84 calculator. In a survey, 19 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $37 and standard deviation of $13. Construct a confidence interval at a 90% confidence level.

Give your answers to one decimal pla

Answer 1

37 ± 5.2

Explanation:

n (sample size) = 19

mean = 17

s (standard deviation) = 13

C = 0.90 or 90% confidence levle

T value = 1.734 given that degrees of freedom (19 -1) and is two-tailed

margin of error = t^s / square root (n)

= 1.734 x 13 / sqrt 19

= 5.17

= 5.2

MoE = 5.2

To get the T value using a Ti-84 calculator, what you do is:

1. press the 2nd function and press [vars]

2. a DISTR screen will show up and select the invT() option

3. for a two tailed test

4. type in the confidence interval, followed by the tail, and then the degrees of freedom

example: invT (.10/2, 18), which is 1.734