2-2, 2-3, 2-4 quiz 2 exam 1

percentage frequency

(class frequency / sum of all frequencies) *2

Histogram: When graphed, a normal distribution has a _____ __________ Characteristic of the bell shape are (1) The frequencies increase to a __________, and then decrease (2) symmetry, with the left half of the graph roughly a __________ image of the right half.

- "bell" shape. -maximum -mirror

The sum of the percentages in a relative frequency distribution must be very close to ___ __________. The sum of proportions in a relative frequency distribution must be _.

-100 percent -1

Daily Low Temperature (°F) Frequency 35-37 1 38-40 3 41-43 5 44-46 11 47-49 7 50-52 7 53-55 1 What is the class​ width? What are the class​ midpoints? What are the class​ boundaries?

-3 -36​, 39​, 42​, 45​, 48​, 51​, 54 -34.5​ 37.5​, 40.5​, 43.5​, 46.5​, 49.5​, 52.5​, 55.5

histogram

-A graph consisting of bars of equal width drawn adjacent to each other (unless there are gaps in the data) -The horizontal scale represents the classes of quantitative data values and the vertical scale represents the frequencies. -The heights of the bars correspond to the frequency values. - graph of frequency distribution

in order for a graph to appear accurate and not exaggerative the vertical line must begin at ____. Which of the following is a common distortion that occurs in​ graphs?

-zero -Using a​ two-dimensional object to represent data that are​ one-dimensional in nature is a bad practice that distorts the meaning of the data. When drawing such​ objects, artists can create false impressions that distort differences.

variation

A measure of the amount that the data values vary

Center:

A representative value that indicates where the middle of the data set is located.

Which of the following is NOT true about statistical​ graphs? Choose the correct answer below. A. They can be used to consider the overall shape of the distribution. B. Similar graphs can be constructed in order to compare data sets. C. They utilize areas or volumes for data that are​ one-dimensional in nature. D. They can be used to identify extreme data values.

C. They utilize areas or volumes for data that are​ one-dimensional in nature

time

Changing characteristics of the data over time.

pareto chart

In a Pareto​ chart, the bars are always arranged in descending order according to frequencies. The Pareto chart helps us understand data by drawing attention to the more important​ categories, which have the highest frequencies.

outliers

Sample values that lie very far away from the vast majority of other sample values.

normal distribution

The frequencies start low, then increase to one or two high frequencies, and then decrease to a low frequency. The distribution is approximately symmetric, with frequencies preceding the maximum being roughly a mirror image of those that follow the maximum.

distribution

The nature or shape of the spread of data over the range of values (such as bell-shaped, uniform, or skewed).

The population of ages at inauguration of all U.S. Presidents who had professions in the military is​ 62, 46,​ 68, 64, 57. Why does it not make sense to construct a histogram for this data​ set?

With a data set that is so​ small, the true nature of the distribution cannot be seen with a histogram.

pie chart

a chart that shows the relationship of a part to a whole

scatter plot

a graph that relates two different sets of data by displaying them as ordered pairs

Upper Class Limits

are the largest numbers that can actually belong to different classes.

Class Boundaries

are the numbers used to separate classes, but without the gaps created by class limits.

Lower Class Limits

are the smallest numbers that can actually belong to different classes.

class midpoint

are the values in the middle of the classes and can be found by adding the lower class limit to the upper class limit and dividing the sum by 2.

relative frequency

class frequency / sum of all frequencies

class midpoint formula

class midpoint = (Lower class limit + upper class limit) ____________________________________________________ 2

class width formula

class width = (maximum value) - (minimum value) ------------------------------------------ number of classes

dot plot

data that is dotted on a horizontal scale

relative frequency histogram

has the same shape and horizontal scale as a histogram, but the vertical scale is marked with relative frequencies instead of actual frequencies

We use a visual tool called a __________ to analyze the shape of the distribution of the data

histogram

Class Width

is the difference between two consecutive lower class limits or two consecutive lower class boundaries

graphs that decieve

nonzero axis, pictograph

Which is more effective Pareto graph or pie chart?

pareto graph

time series graph

quantitative data that has been collected at different points in time

stemplot

represents quantative data by seperating each value into two parts. The stem and the leaf

graphs that enlighten

scatter plot, dot plot, time series plot, stemplot, pie chart, frequency polygon graph

Frequency Distribution(or Frequency Table)

shows how a data set is partitioned among all of several categories (or classes) by listing all of the categories along with the number (frequency) of data values in each of them. indicates the shape and nature of the distribution of a data set.

How to find the class width looking at a histogram?

subtracting the minimum value from the maximum value of the consecutive lower classes. In this example the class width is 20.

cumulative frequency

the sum for that class and each previous class before that

frequency polygon

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