Consider the report cards for Sam and Samantha given below.

Sam		Samantha
Credits	Letter Grade	Credits	Letter Grade
5	C	6	F
1	C	3	C
6	D	4	C
4	C	3	D
6	D	4	F

(a) Calculate Sam's GPA.

(b) Calculate Samantha's GPA.

Most credit cards charge interest based on the average daily balance per billing cycle. In this case each balance within the billing cycle is weighted by the number of days it exists. Suppose your credit card has a 30 day billing cycle and the balances over these 30 days are given in the table below.

Days	Transaction	balance	# days
1-6	remaining balance	$1900	6
7-13	$400 purchase	$2300	7
14-17	$1000 purchase	$3300	4
18-30	$1500 payment	$1800	13

(a) Calculate the average daily balance for these 30 days.

(b) What would have been your average daily balance if you paid $1400 on day 15 instead of $1500 on day 18?

Below is a frequency distribution for the estimated miles per gallon (MPG) for 288 different models of Japanese-made cars.

Japanese-Made Cars
MPG	Frequency
9 - 12	8
13 - 16	37
17 - 20	103
21 - 24	90
25 - 28	27
29 - 32	18
33 - 36	1
37 - 40	0
41 - 44	2
45 - 48	2

(a) Identify the following

class midpoints (enter as a comma-separated list)

class boundaries (enter as a comma-separated list)

class width

(b) Create a relative frequency table from the frequency table.

Japanese-Made Cars
MPG	Relative Frequency
9 - 12	%
13 - 16	%
17 - 20	%
21 - 24	%
25 - 28	%
29 - 32	%
33 - 36	%
37 - 40	%
41 - 44	%
45 - 48	%

(c) Create a cumulative and relative-cumulative frequency table.

Japanese-Made Cars
MPG	Cumulative Frequency	Relative Cumulative Frequency
less than 12.5		%
less than 16.5		%
less than 20.5		%
less than 24.5		%
less than 28.5		%
less than 32.5		%
less than 36.5		%
less than 40.5		%
less than 44.5		%
less than 48.5		%

(d) Estimate the mean MPG for the Japanese-made cars included in this set.