Compare Two Populations Using Data Practice Test

A teacher randomly sampled 7 words from a 7th-grade science article and 7 words from a 4th-grade science article and counted the number of letters in each word.

7th grade (letters): 5, 6, 4, 7, 5, 6, 5

4th grade (letters): 3, 4, 3, 5, 4, 3, 4

About how much larger is the difference in the means (7th grade minus 4th grade)?

A store compared checkout times (in minutes) for two cashiers. A random sample of 8 customers was recorded for each cashier.

Cashier A: 4, 5, 6, 5, 4, 6, 5, 5

Cashier B: 3, 7, 4, 8, 5, 6, 4, 7

Which statement is correct about the sample means and ranges?