Chapter 1
Parameter or Statistic?
According to a school district’s records, 92% of all enrolled students have access to the internet at home.
Parameter
What did Dr. Johnson compare skewed graphs to?
Feet
Find the mean, median, and mode for the following data set.
40, 99, 83, 83, 28, 63
Mean = 66
Median = 73
Mode = 83
Petroleum pollution in oceans stimulates the growth of certain bacteria. An assessment of this growth has been made by counting the bacteria in each of 6 randomly chosen specimens of ocean water (of a fixed size). The 6 counts obtained were as follows.
54, 53, 69, 59, 40, 67
Find the standard deviation of this sample of numbers. Round your answer to two decimal places.
10.6
The three quartiles for systolic blood pressure in a sample of 3164 men Q1 = 97, Q2 = 118, and Q3=139.
Find the IQR.
42
Determine whether the data described are nominal or ordinal.
My grades this semester were C, D, A, and B.
Ordinal
Slide #10
Graph A, Skewed right
Graph B, Skewed left
In a study of Facebook users conducted in a recent year, the mean number of Facebook friends per user was 266 and the median was 260. If a histogram were constructed for the numbers of Facebook friends for all Facebook users, would you expect it to be skewed to the right, skewed to the left, or approximately symmetric?
Approximately symmetric
Slide #18
All or almost all
For the data set:
35, 34, 41, 66, 16, 11, 37, 21, 3, 26, 81
Find the first and third quartiles.
What is the IQR?
The first quartile is 16.
The third quartile is 41.
The IQR is 25.
Determine whether the data described are qualitative or quantitative.
Height of skyscrapers.
Quantitative
Slide #11
10 Classes
Class width of 7
Slide #14
Mean: 23.375
Median: 27.5
Mode: 28
Slide #19
2.0
If your score in your math class puts you in the 60th percentile, what exactly does that mean?
60% of the scores in your class were less than yours.
Determine the sample method:
To understand dining preferences, Kennesaw State’s campus dining services divide students into groups based on meal plan type: Unlimited Access, Weekly Meals, Dining Dollars Only, and No Meal Plan. They then randomly select 10 students from all groups to take a survey.
Stratified
Slide #21
A
The number of calories in a sample of hamburgers from six fast food restaurants is 350, 370, 262, 300, 240, 350.
Compute the mean and median.
Mean: 312
Median: 325
Slide #20
Region 1 is 6.6.
Region 2 is 7.0.
Region 2 has the greater spread.
A population has mean μ=22 and standard deviation σ=6. Round the answers to two decimal places as needed.
Find the z-score for a population value of 3.
-3.17
Determine the type of bias involved:
A teacher draws a sample of 50 students and asks them if they do their homework regularly between class periods. 78% of the students said that they do.
Nonresponse, voluntary response, social acceptability, self-interest.
Social acceptability
List the data in the following stem-and-leaf plot. The leaf represents the tenths digit.
14 |
15 | 4
16 | 0114
17 | 0
18 | 2257
15.4, 16.0, 16.1, 16.1, 16.4, 17.0, 18.2, 18.2, 18.5, 18.7
Jermaine has entered a bowling tournament. To prepare, he bowls five games each day and writes down the score of each game, along with the mean of five scores. He is looking at the scores from one day last week and finds that one of the numbers has accidentally been erased. The four remaining scores are 266, 268, 239, and 275. The mean score of the five games is 255. What is the missing score?
227
In a large sample of customer accounts, a utility company determined that the average number of days between when a bill was sent out and when the payment was made is 26 with a standard deviation of 3 days. Assume the data to be approximately bell-shaped.
Estimate the percentage of bills for which payment was made in greater than 29 days.
16%
In a particular year, the mean score on the ACT test was 17.3 and the standard deviation was 3.6. The mean score on the SAT mathematics test was 526 and the standard deviation was 107. The distributions of both scores were approximately bell-shaped. Round the answers to at least two decimal places.
A.) Find the z-score for an ACT score of 20.
B.) Find the z-score for a SAT score of 531.
C.) Jose's ACT score had a z-score of 0.51. What was his ACT score?
0.75
0.05
19.14