ISSCM CH1-4 Exam mult choice questions

In constructing a frequency distribution, the approximate class interval is computed as

(maximum value − minimum value) ÷ (number of classes).

In a marketing study, 100 consumers were asked to select their favorite type of mattress: foam, latex, hybrid, or inner spring. To summarize the consumer responses with a frequency table, how many classes would the frequency table have?

4 classes

The median of a sample will always equal the ____

50th percentile

Which of the following statements is true about the correlation coefficient?

A correlation coefficient of zero means that two quantitative variables are not linearly related to each other.

What is the difference between a histogram and a bar chart?

A histogram is used to display quantitative data and a bar chart is used to display qualitative data.

A correlation coefficient of +0.08 indicates strong positive correlation. T/F

FALSE

Extremely high or low scores affect the value of the median. T/F

FALSE

For a set of data arranged or sorted in numerical order, the value of the observation in the center is called the weighted mean. T/F

FALSE

For any distribution, there is an equal number of values above and below the mean. T/F

FALSE

Which one of the following is referred to as the population mean?

µ

In a scatter diagram, we describe the relationship between __

two variables measured at the interval or ratio level

In a contingency table, we describe the relationship between _____

two variables measured at the ordinal or nominal level

A population is a collection of all individuals, objects, or measurements of interest. T/F

true

In a company, the standard deviation of the ages of female employees is 6 years and the standard deviation of the ages of male employees is 10 years. These statistics indicate that the dispersion of age is greater for females than for males. T/F

FALSE

Quartiles divide a distribution into 10 equal parts. T/F

FALSE

Which of the following statements about frequency polygons is FALSE?

Frequency polygons do not show the shape of a distribution.

A box plot shows the skewness of a distribution. T/F

TRUE

A correlation coefficient of −0.8 indicates strong indirect relationship. T/F

TRUE

Frequency polygons depict the data from a frequency distribution using the class midpoints for the horizontal axis coordinates and the class frequencies for the vertical axis coordinates. T/F

TRUE

If production determines sales, then a scatter diagram of these two variables is labeled with sales on the Y-axis and production on the X-axis. T/F

TRUE

In frequency distributions, classes are mutually exclusive if each individual, object, or measurement is included in only one category. T/F

TRUE

Percentiles divide a distribution into 100 equal parts T/F

TRUE

The "box" in a box plot shows the interquartile range. T/F

TRUE

The arithmetic mean is the sum of the quantitative observations divided by the total number of observations. T/F

TRUE

The correlation coefficient measures the strength and direction of the relationship between two quantitative variables. T/F

TRUE

The mode is the value of the observation that appears most frequently. T/F

TRUE

To convert a frequency distribution to a relative frequency distribution, divide each class frequency by the sum of the class frequencies. T/F

TRUE

To infer something about a population, we usually take a sample from the population. T/F

TRUE

What statistics are needed to draw a box plot?

The minimum, maximum, median, first and third quartiles

What does the interquartile range describe?

The range of the middle 50% of the observations

What is the relationship between the variance and the standard deviation?

Variance is the square of the standard deviation.

Sometimes, a data set has two values that have the highest and equal frequencies. In this case, the distribution of the data can best be described as _________blank.

bimodal (having two modes)

A disadvantage of using an arithmetic mean to summarize a set of data is that the arithmetic mean _________.

can be biased by one or two extremely small or large values

Explain the difference between a discrete and a continuous variable

discrete variables can assume only certain values, but continuous variables can assume any values within some range

In order to convert class frequency to relative class frequency, we

divide the frequency of the class by the sample size.

For any data set, which measures of central location have only one value?

mean and median

For a data set, half of the observations are always greater than the _________.

median

In a distribution, the second quartile corresponds with the ________

median

Which measures of central location are not affected by extremely small or extremely large values?

mode and median

A dot plot can be used to quickly determine which values?

mode median range

Which word is not part of the definition of descriptive statistics?

predicting

explain the difference between qualitative and quantitative variable

qualitative data is not numerical, whereas quantitative data is numerical

a pie chart shows the

relative frequencies of a qualitative variable

A table summarizing a set of data showing the fraction of the total number of items in several classes is a

relative frequency table

A portion or part of a population is called a

sample

When statisticians analyze sample data in order to draw conclusions about the characteristics of a population, this is referred to as

statistical inference

A company wishes to know whether advertising expenditure is related to sales volume. Using the past two years of data for these two variables, they determined the correlation coefficient is +0.93. This indicates a _________blank relationship between advertising expenditure and sales volume.

strong direct

The main purpose of descriptive statistics is to

summarize data in a useful and informative manner.

Which of the following is not a measure of dispersion?

the 50th percentile

When data are collected using a qualitative, nominal variable (e.g., drink sizes like small, medium, or large), what is true about a frequency table that summarizes the data?

the number of classes corresponds to the number of a variable's values

For a data set with an odd number of observations that have been sorted from smallest to largest values, where is the median located?

the observation in the middle

The 67th percentile is __

the value below which 67% of the observations occur

What is the relationship among the mean, median, and mode in a symmetric distribution?

they are all equal