Question

In a study of reaction times to a specific stimulus, a psychologist recorded these data (in seconds). Find the variance and standard deviation. Use a TI-83 Plus/TI-84 Plus calculator and round the answers to at least two decimal places.

Answer 1

Answer:

s² = 0.7965

s = 0.8925

Step-by-step explanation:

Given the data :

Class limit __ midpoint(x) ___ Frequency

2.1 - 2.7 ______2.4 ________13

2.8 - 3.4 ______3.2 _______ 14

3.5 - 4.1 ______ 3.8 _______ 10

4.2 - 4.8 ______4.5 _______ 6

4.9 - 5.5______ 5.2 ________2

5.6 - 6.2______ 5.9 ________ 1

The midpoint was calculated thus :

(Upper limit + lower limit) / 2

Using a graphing calculator :

The sample variance, s² = 0.7965

The sample standard deviation, s = 0.8925