Question 1

A(n) _____ is often seen in negatively skewed distributions, while a(n) _____ is often seen in positively skewed distributions.

Accepted Answer

The answer of A(n) _____ is often seen in negatively...

Question 2

Of the different types of distributions, which distribution is described by a tail that extends to the left?

Accepted Answer

A negatively skewed distribution is one in which the tail extends to the left, meaning that the majority of the data is concentrated on the right side of the distribution.

Question 3

Floor effects can lead to positive skew in a distribution.

Accepted Answer

Floor effects occur when a large number of participants score at the lower end of a measurement instrument, which can cause a distribution to be skewed towards the higher end. This is because participants cannot score lower than the lowest possible score on the instrument, resulting in a clustering of scores at the lower end and a longer tail towards the higher end, leading to positive skew.

Question 4

Dr.Choi is examining the weights of 750 children, 2 to 18 years old, to find out if childhood obesity rates are increasing in his city.With this type of data, is it better to use a frequency table or a grouped frequency table? Why?

Accepted Answer

A grouped frequency table is better because the data are a large set of continuous intervals. The age range of 2 to 18 years for 750 children will result in a large range of weights, which is better presented using intervals in a grouped frequency table. This will make the data more manageable to analyze and easier to present visually. A frequency table is typically used for data that is more discrete and covers a smaller range.

Question 5

Some sports have what is called a "mercy rule," that is, once the difference in scores between two teams gets to a certain level, the game is ended.In soccer, the mercy rule might end a game when one team has 15 more goals than the other team.This limit on how big the difference between points can be is an example of a ceiling effect.

Accepted Answer

The passage states that "This limit on how big the difference between points can be is an example of a ceiling effect."

Question 6

Ceiling effects can lead to negative skew in a distribution.

Accepted Answer

Ceiling effects occur when a large proportion of the scores in a dataset reach the maximum score possible, resulting in a restriction of range. This can cause a distribution to have a lack of variability in the higher scores, which can lead to a negative skew.

Question 7

When creating histograms and frequency polygons, the x-axis typically represents _____ and the y-axis represents _____.

Accepted Answer

The x-axis typically represents values or intervals (the categories or ranges being measured), while the y-axis represents frequencies (the counts or number of occurrences of each value or interval).

Question 8

In a negatively skewed distribution, the tail extends to the left.

Accepted Answer

In a negatively skewed distribution, the tail is longer on the left side and the majority of the scores are concentrated on the right side.

Question 9

What type of graph displays individual data points of one variable both numerically and visually?

Accepted Answer

A stem-and-leaf plot displays individual data points both numerically and visually, by showing the stems (leading digits) and the leaves (trailing digits) of each data point.

Question 10

A stem-and-leaf plot offers an advantage over a histogram in that it shows the data both visually and numerically, whereas a histogram displays the data visually only.

Accepted Answer

A stem-and-leaf plot does show the data both visually and numerically, whereas a histogram only shows the data visually.

Question 11

Ceiling effects can lead to positive skew in a distribution.

Accepted Answer

Ceiling effects can lead to a negative skew in a distribution because scores are bunched at the high end, limiting the range of higher scores and causing the distribution to skew left (toward the lower scores).

Question 12

A _____ is a data point that has not yet been manipulated.

Accepted Answer

A raw score is a data point that has not yet been manipulated, while a frequency distribution, normal distribution, and positively skewed distribution are all ways of organizing and representing data.

Question 13

The EPA noticed a large increase in the output of greenhouse gases from automobile traffic between 1996 and 1998 in California.When the agency looked at the data by city, it noticed that the score for Los Angeles was significantly higher than that for the other major cities in California combined.How was the city skewing the distribution?

Accepted Answer

The city of Los Angeles was skewing the distribution positively, causing the overall score for greenhouse gas output to be higher for California.

Question 14

People who report "married" as their relationship status are assumed to have no less than one marriage.The fact that the number of marriages cannot vary below one represents a ceiling effect.

Accepted Answer

The statement describes a floor effect, not a ceiling effect, because it sets a minimum (not maximum) limit on the number of marriages.

Question 15

The numbers of avalanche fatalities in Colorado for the last eight seasons were reported as 1, 1, 5, 5, 5, 5, 8, and 10.Roughly what type of distribution is shown?

Accepted Answer

The answer of The numbers of avalanche fatalities in Colorado...

Question 16

Mark is looking at a histogram depicting students placed in various high schools.In this histogram, the x-axis most likely represents the _____ while the y-axis most likely represents the _____.

Accepted Answer

In a histogram, the x-axis typically represents the values of the variable being measured (in this case, different high schools), and the y-axis represents the frequencies or number of observations (in this case, the number of students placed in each high school).

Question 17

In a side-by-side stem-and-leaf plot, data from unrelated variables are often presented so that they might be compared.

Accepted Answer

In a side-by-side stem-and-leaf plot, data from related variables or groups are presented for comparison, not unrelated variables.

Question 18

A graduate statistics class is unhappy with the midterm grades.The majority of students scored 45 or below on a 100-point scale, with just several students performing very well.Which type of distribution do the test scores represent?

Accepted Answer

The majority of the scores being low (45 or below) and only a few students performing well indicates a tail that extends towards the higher values, resulting in a positively skewed distribution. A normal distribution would have a roughly symmetrical shape, and a negatively skewed distribution would have a tail extending towards the lower values. Nominal refers to a type of categorical data, which is not relevant in this context.

Question 19

The two most common methods for graphing interval data for one variable are the _____ and the _____.

Accepted Answer

The two most common methods for graphing interval data for one variable are the histogram and the frequency polygon. A grouped frequency table is used to organize the data before creating a histogram or frequency polygon. Therefore, option A and C are not correct. Option B is partially correct but does not include the histogram, which is a commonly used graph for interval data.

Question 20

Floor effects can lead to negative skew in a distribution.

Accepted Answer

Floor effects can lead to positive skew in a distribution because they limit how low scores can go, causing a pile-up at the lower end and a longer tail towards the higher end.

Quiz 2: Frequency Distributions

A(n) _ is often seen in negatively skewed distributions, while a(n) _ is often seen in positively skewed distributions.