STAT Module 2 EXAM

What is a pareto chart?

A bar graph whose bars are drawn in decreasing order of frequency or relative frequency

What is an ogive?

A graph that represents the cumulative frequency or cumulative relative frequency for the class

For IQ scores of students, state whether you would expect a histogram of the data to be bell shaped, uniform, or curved

Bell shaped

T or F, correlation implies causation.

False

A histogram of a set of data indicates that the distribution of the data is skewed right. Which measure of central tendency will be larger, the mean or the median why?

The mean will likely be larger because the extreme values in the right tail tend to pull the mean in the direction of the tail

What makes range less desirable than the standard deviation as a measure of dispersion?

The range does not use all the observations

In a relative frequency distribution, what should the relative frequencies add up to?

The relative frequencies should add up to 1

What does it mean to say that two variables are positively associated?

There is a linear relationship between the variables and whenever the value of one variable increases, the value of the other variable increases.

T or F, when comparing two populations, the larger the standard deviation, the more dispersion the distribution has, provided that the variable of interest from the two populations has the same unit of measure.

True, because the standard deviation describes how far, on average, each observation is from the typical value. A larger standard deviation means that observations are more distant from the typical value, and therefor more dispersed.

T or F, Chebyshev's inequality applies to all distributions, regardless of shape, but the empirical rule holds only for distributions that are bell shaped.

True: Chebyshev's inequality is less precise than the empirical rule, but will work for any distribution, while the empirical rule only works for bell shaped distributions

What is a bar graph?

a horizontal or vertical representation of the frequency or relative frequency of the categories. the height of each rectangle represents the category's frequency or relative frequency

The ___ is the difference between consecutive lower class limits

class width

___ are the categories by which data are grouped

classes

The ___R^2, measures the proportion of total variation in the response variable that is explained by the least squares regression line.

coefficient of determination

T or F, stem and leaf plots are particularly useful for large sets of data?

false

T or F: a data set will always have exactly one mode

false

Suppose a person claims that 4.2% of all people in the nation always eat out. is this a descriptive or inferential statement?

inferential

If the results of a survey were claimed to indicate that 7.8% of adults in this country who own digital cameras plan to replace their cameras in the next 12 mo. would you say this statement is descriptive or inferential, why?

inferential b/c the survey reports on a sample of the country's population. this claim requires an inference to the population

The ___ is the smallest value within the class and the ___ is the largest value within the class

lower class limit, upper class limit

A histogram of a set of data indicates that the distribution of the data is skewed right. Which measure of central tendency will likely be larger, the mean or the median?

mean, because the extreme values in the tail tend to pull the mean in the direction of the tail

If the linear correlation between two variables is negative, what can be said about the slope of the regression line?

negative

A local news broadcast reported 8.2% of tickets purchased from the airline are flights to San Diego. what is wrong with this statement?

no level of confidence was provided along with the estimate

The frequency distribution lists the ___ of occurrences of each category of data, while relative frequency distribution lists the ___ of occurrences of each category of data

number, proportion

A ___ is a scatter diagram with the residuals on the vertical axis and the explanatory variable on the horizontal axis

residual plot

In a boxplot, if the median is to the left of the center of the box and the right whisker is substantially longer than the left whisker, the distribution is skewed___

right

What is a residual? What does it mean when a residual is positive?

the difference between an observed value of the response variable y, and the predicted value of y. if it s positive, then the observed value is greater than the predicted value