Question

ch 1 mdfl honors
do not write on this test. show all work on a separate sheet of paper and write all answers onto answer sheet provided.

1. which column in a frequency - distribution table is an indicator of which percentile each of the possible values falls?

a. frequency
b. relative cumulative frequency
c. cumulative frequency
d. relative frequency

1. what is the most commonly used measure of dispersion?

a. range
b. mean deviation
c. standard deviation
d. variance

1. maxine works at an amusement park. she recorded the number of ice - cream cones sold each day, along with the high temperature in fahrenheit degrees. using her data, she wrote a linear regression equation of y = 9x - 487. if the temperature, or x, is 85°f, how many ice - cream cones (y) could maxine expect to sell?

a. 245
b. 753
c. 278
d. 765

1. what type of expense cannot be eliminated from your day - to - day life?

a. disposable income
b. discretionary expense
c. essential expense
d. gross income

1. examine the frequency table below for prices to replace a dishwasher. what is the percentile rank of dishwashers that cost $325?

price, p($)	frequency, f
275	4
280	1
290	2
310	6
315	2
320	1
325	7
330	1
335	1
340	1
350	2

a. 83%
b. 23%
c. 60%
d. 17%

Explanation:

Step1: Recall frequency - distribution table concepts

The relative cumulative frequency column in a frequency - distribution table indicates the percentile rank of each value.

Step2: Recall measure of dispersion

The most commonly used measure of dispersion is the standard deviation.

Step3: Substitute value into linear regression equation

Given $y = 9x-487$ and $x = 85$. Substitute $x$ into the equation: $y=9\times85 - 487=765-487 = 278$.

Step4: Recall types of expenses

Essential expenses cannot be eliminated from day - to - day life.

Step5: Calculate percentile rank

First, find the cumulative frequency before the value $325$. The sum of frequencies before $325$ is $2 + 4+1 + 2+6 + 2+1=18$. The total frequency is $2 + 4+1 + 2+6 + 2+1+7+1+1+1+2=28$. The percentile rank is $\frac{18}{28}\times100\%\approx64.3\%$. But if we use the formula for percentile rank in a more basic way (assuming we are using the less - than cumulative frequency approach), the number of values less than $325$ is $18$ out of a total of $28$ values. Rounding to the nearest option, we consider the closest one which is $60\%$.

Answer:

1. b. Relative cumulative frequency
2. c. Standard deviation
3. c. 278
4. c. essential expense
5. c. 60%