Stats 230 Ch.2

In the grouped frequency table of placement test scores shown above, the midpoint of the lowest class is

0+9/2=4.5

A bimodal distribution has __________ modes.

two

The relative frequency of the second class is ______%.

1/25=0.04 0.04*100= 4%

You previously found the mean of this data set. Use that in answering the question. 63, 89, 92, 73, 79, 72, 34, 36, 94, 21, 25, 93, 22, 90, 79 Calculate the sum of squares of the data set.

11239.733

A grouped frequency table is likely to have between 5 and ________ classes.

15

The cumulative frequency of the last class is ____.

25

If a grouped frequency table has five classes with the first class 1 - 13, the lower limit of the third class should be

27

Ten students took a placement test to see if they could bypass a prerequisite requirement for a course. Out of 100 points possible, the scores were: 45, 62, 63, 58, 81, 77, 64, 69, 82, 51. The student who scored 69 was at what percentile?

60th percentile

If 2 out of 3 dentists recommend a certain kind of gum, what percentage of dentists is that, rounded to the nearest whole number? A 67 B 33 C 80 D 59

67

You previously found the mean of this data set. Use that in answering the question. 63, 89, 92, 73, 79, 72, 34, 36, 94, 21, 25, 93, 22, 90, 79 Calculate the sample variance of the data set.

802.8381802.8381

Ten students took a placement test to see if they could bypass a prerequisite requirement for a course. Out of 100 points possible, the scores were: 45, 62, 63, 58, 81, 77, 64, 69, 82, 51. What were the scores of the students who scored above the third quartile? Separate your answer with a comma and a space.

81,82

A negative skew may have a tail that indicates extreme scores __________ the center of the distribution. A Around B Below C Above D On either side of

Below

he bars representing data touch each other in a ______. A Histogram B Bar chart C Polygon D Frequency table

Histogram

Which of the following is not a type of frequency distribution? A Inferential table B Frequency polygon C Histogram D Pie chart

Inferential Table

What do your answers to the previous three questions tell you about the distribution?

It is unimodal and negatively skewed

Numbers that describe samples are called

Statistics ?

An instructor calculates the grades on the first exam for her statistics class. She finds that students did really well, with most students scoring 98 or higher. This type of effect, which often corresponds to a negatively skewed distribution, is described as a __________ effect.

ceiling

63, 89, 92, 73, 79, 72, 34, 36, 94, 21, 25, 93, 22, 90, 79 Calculate the median of the data set.

put them in order and cancel them all out to 73

The most frequently occurring score in a distribution is the

mode

Use the following data set to answer the question: 63, 89, 92, 73, 79, 72, 34, 36, 94, 21, 25, 93, 22, 90, 79 Calculate the mode of the data set.

most common data unit=79

The mean of the population is represented by the symbol

mu

Use the following data set to answer the question: 63, 89, 92, 73, 79, 72, 34, 36, 94, 21, 25, 93, 22, 90, 79 Calculate the mean of the data set.

63+89+92+73+79+72+34+36+94+21+25+93+22+90+79= 962= 962/15= 64.13

How do histograms differ from bar graphs? A Histograms are typically used to depict frequencies of continuous data, but bar graphs are typically used to depict categorical data. B Histograms are typically used to depict categorical data, but bar graphs are typically used to depict frequencies of continuous data. C Histograms are typically used to depict means, but bar graphs are typically used to depict frequencies. D Histogram is just another word for bar graph—the two graphs do not differ.

Histograms are typically used to depict frequencies of continuous data, but bar graphs are typically used to depict categorical data.

Numbers that describe populations are called

Parameters

Bar Chart

Shows frequencies of categories

Which of the following accurately describes the axes of a histogram? A The y-axis shows categories of data; the x-axis shows observed values B The x-axis shows the frequency; the y-axis shows categories of data C The y-axis shows observed values; the x-axis shows categories D The x-axis shows the variable values; the y-axis shows frequency

the x-axis shows the variable values; the y-axis shows frequency

You previously found the mean of this data set. Use that in answering the question. 63, 89, 92, 73, 79, 72, 34, 36, 94, 21, 25, 93, 22, 90, 79 Calculate the sample standard deviation of the data set.

28.3344

Histogram

Shows frequencies of numerical data

A positive skew may have a tail that indicates extreme scores __________ the center of the distribution. A Around B Below C Above D On either side of

Above

With a frequency polygon, what does grounding the shape mean? A Making sure all data are accurate and honest B Connecting it to the frame of the graph with lines C Adding a value on both ends of the axis so lines can be drawn to zero

Adding a value on both ends of the axis so lines can be drawn to zero

What are raw data points? A Data points in their original form B Data points that have been manipulated in some way C Data points in a frequency polygon D Data points that the researcher has discarded because they appear in error

Data points in their original form

A grouped frequency table is most useful when which of the following is true? A Scores in the data set vary over a small range of discrete values B Data are ordinal C Data vary over a large range of continuous values D Data are nominal

Data vary over a large range of continuous values

In a frequency polygon, the y-axis represents the __________. A Midpoint for every interval B Frequencies C Raw scores D Total number of participants in the study

Frequencies

A ________ is a structured presentation of data that shows discrete data values, or scores, together with the frequency of each score. A Frequency calculation B Frequency table C Histogram D Frequency polygon

Frequency Table

Researchers often want to understand individual variables and the values observed. Rather than examining a long list of numbers, they might consider organizing and displaying the values using a: A Scale variable B Raw data sorter C Inferential model D Frequency table

Frequency Table

A ________ is a structured presentation of data based on frequencies of classes rather than frequencies of specific values. A Grouped frequency table B Frequency table C Frequency polygon D Normal distribution

Grouped frequency table

Ten students took a placement test to see if they could bypass a prerequisite requirement for a course. Out of 100 points possible, the scores were: 45, 62, 63, 58, 81, 77, 64, 69, 82, 51. What is Q2 on this administration of the test?

It is the median, which is 63.5

School-aged children are regularly asked to fundraise for their school. Typically, they are required to sell a minimum amount. This mandate results in most students selling that minimum, with some exceptional children selling far larger quantities. The minimum sales constraint that likely causes positively skewed data is consistent with a __________ effect.

floor

A ________ table is often used to display data when the data have a very large range of values.

grouped frequency