Math Chapter 12

Population

all data

Sample

part of data

Random samples have equal chance (True or False)

True

Data collected in its original form

Raw data

Raw data distributed by frequency

frequency distribution

Lower limit

Smallest number in class

Upper limit

Greatest number in class

Width between classes is what

consistent

How to solve for class width

diff. between lower/upper limits

When solving for range do you look at the distribution or raw data

raw

Histograms need to

touch

What is a frequency polygon

Line graph of the points used for a histo

Mode

Most

Mean is affected by

outliers

Population mean symbol looks like what

weird u

Sample mean symbol looks like what

x with line on top

True or false: You solve for population/sample mean the normal way you solve for mean

True

Median is unaffected by

outliers

Which central tendencies are still trustworthy even with an outlier

Median mode

Mode is unaffected by

outliers

x¯=∑(f·x)/

∑f

frequency distribution mean

In frequency distribution mean formula what does the x mean

data

In frequency distribution mean formula what does the f mean

Frequency

∑

Add all total

Midrange formula

lowest data + highest data/2

What is variation

how far it is from center

Bell curve: Higher values make what

shorter curve

Why is range not always accurate

Affected by outliers, ignores data distribute

Lower variability means what

More consistency

Deviation

how diff is it from the mean

Population SD formula

Sample SD formula

Unusual value

2+ SD from mean

Very unusual (outlier)

3+ SD from mean

Can never be negative because it is distance

SD

What is SD if all entries are the same

zero

x minus x with a bar on top all divided by SD

z score

If you are solving for the right side of a bell curve what do you do

1-z score

How do you know If you are solving for the right side of a bell curve

look for “above”

True or False: If 80% of the group are shorter than you then you are 80th percentile

True

When you are solving for percentile do you count all numbers except the one you’re looking for (count all smaller numbers)

yes

Median of lower 50% of data values

Q1

Median of upper 50% of data values

Q3

Median of entire data set

Q2

Mean and SD can be anything

Normal distribution

Mean is zero and SD=1

Standard normal distribution

Data items cluster around mean

normal distribution

Highest peak is mean

Normal distribution

Normal distribution total area under curve is

100% or 1

Normal distribution as sample size increases prediction becomes what

more accurate

Histogram: Highest values are on the left side

Right positive

Histogram: Highest values are on the right side

Left negative

Right positive histogram

mode less than median less than mean

Left negative

mode greater than median greater than mean

z score table only gives you what

left side value

68% data falls within SD

68% rule

95% data falls within 2 SD

95% rule

99.7% data falls within 3 SD

99.7% rule