CH 2 Exploring Data With Tables and Graphs Flashcards Preview

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Flashcards in CH 2 Exploring Data With Tables and Graphs Deck (34)
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1
Q

What term shows how data are partitioned among several categories (or classes) by listing the categories along with number (frequency) of data values in each of them?

A

Frequency distribution (Frequency table)

2
Q

In regards to constructing frequency distributions, what term describes the smallest numbers that can belong to each of the different classes?

A

Lower class limits

3
Q

In regards to constructing frequency distributions, what are the largest numbers that can belong to to each of the different classes?

A

Upper class limits

4
Q

In regards to constructing frequency distributions, what are the numbers used to separate the classes, but without the gaps created by class limits?

A

Class boundaries

5
Q

In regards to constructing frequency distributions, what term describes the values in the middle of the classes?

A

Class midpoints

6
Q

In regards to constructing frequency distributions, what term describes the difference between two consecutive lower class limits in a frequency distribution?

A

Class width

7
Q

What term describes when each class frequency is replaced by a percentage?

A

relative frequency distribution

8
Q

How do you calculate the relative frequency for a class?

A

(frequency for a class) / (Sum of all frequencies)

9
Q

What variation of frequency distribution is used when the frequency of each class is the sum of the frequencies for that class and all previous classes?

A

cumulative frequency distribution

10
Q

What are some characteristics of approximately normal frequency distribution?

A

Frequencies start low, then increase to one or two high frequencies, and then decrease to a low frequency
The distribution is approximately symmetric

11
Q

What does the presence of gaps in a frequency distribution suggest?

A

data are from two or more different populations

12
Q

What term describes a graph consisting of bars of equal width drawn adjacent to each other where the horizontal scale represents classes of quantitative data values and the vertical scale represents frequencies?

A

histogram

13
Q

List the important uses of a histogram:

A

Visually displays the shape of the distribution of the data
Shows the location of the center of the data
Shows the spread of the data
Identifies outliers

14
Q

What has the same shape and horizontal scale as a histogram but the vertical scale uses relative frequencies?

A

Relative frequency histogram

15
Q

What are four common histogram distribution shapes?

A

Bell shaped
Uniform distribution
Skewed to the right
Skewed to the left

16
Q

What is the criteria for assessing normality with a Normal Quantile Plot?

A

Normal distribution: pattern is in reasonably close to a straight line and the points do not show some systematic pattern

17
Q

What type of graph consists of quantitative data in which each data value is plotted as a point above a horizontal scale of values?

A

dotplot

18
Q

What type of graph represents quantitative data by separating each value into two parts: the stem and the leaf?

A

stempot

19
Q

What type of graph is made of quantitative data that has been collected at different points in time?

A

Time-series graph

20
Q

What type of graph uses bars of equal width to show frequencies of categories of categorical data?

A

Bar graphs

21
Q

What is a bar graph with the added stipulation that the bars are arranged in descending order?

A

Pareto Chart

22
Q

What is a common graph that depicts categorical data as slices of a circle, in which the size of each slice is proportional to the frequency count for the category?

A

Pie Charts

23
Q

What uses line segments connected to points located directly above class midpoint values?

A

Frequency Polygon

24
Q

What is a variation of the frequency polygon that uses relative frequencies?

A

relative frequency polygon

25
Q

What are the advantages of the relative frequency polygon?

A

two or more can be combined on a single graph for easy comparison

26
Q

List two ways graphs can be deceptive:

A

Nonzero vertical axis

Pictographs

27
Q

What exists when the values of one variable are somehow associated with the values of the other variable?

A

correlation

28
Q

What exists between two variables when there is a correlation and the plotted points of paired data result in a pattern that can be approximated by a straight line?

A

linear correlation

29
Q

What is a plot of paired (x,y) quantitative data with a horizontal x-axis and vertical y-axis?

A

scatterplot or scatter diagram

30
Q

what is denoted by r, and measures the strength of the linear association between two variables?

A

linear correlation coefficient

31
Q

What does the computed value of the linear correlation coefficient always fall between?

A

-1 and 1

32
Q

Regarding linear correlation coefficient, an r value close to what number implies all the data fall exactly on a line?

A

1 or -1

33
Q

What r value indicates that there is weak or no linear correlation?

A

if r is close to 0

34
Q

When given a collection of paired sample data, what is the straight line that best fits the scatterplot of the data?

A

Regression line