A psychologist monited the heart rates of 5 randomly selecte

A psychologist monited the heart rates of 5 randomly selected college students watching a scary movie. The table shows values for x=the highest (or peak) heart rates attained by each student. The bottom row gives to sum for each column.

1. Find the sample mean.
2. Find the standard deviation for the sample.
3. Find a 90% confidence interval for the mean peak heart rates of college students watching this movie.

Solution

Given that, A psychologist monited the heart rates of 5 randomly selected college students watching a scary movie. The table shows values for x=the highest (or peak) heart rates attained by each student. The bottom row gives to sum for each column.

By using TI-83 calculator we get all the answers of questions.

Steps in TI-83 calculator :

START --> STAT --> ENTER --> Enter data values in L1 --> STAT --> TESTS --> 8:TInterval --> ENTER --> Highlight on Data --> List : select L1 (by clicking on 2nd and 1) --> Freq : 1 --> C-level : 0.90 --> Calculate --> ENTER

Here we use T-interval because sample size is small and population standard deviation is unknown.

Output is,

TInterval =(123.01, 134.99)

sample mean (xbar) = 129

sample standard deviation (Sx) = 6.2849

sample size (n) = 5

The 90% confidence interval for the mean peak heart rates of college students watching this movie is (123.01, 134.99).