Statistics Exam 2

Question 1

population

Answer 1

the entire group of objects to be studied

Question 2

sample

Answer 2

a subgroup of a population on which data is actually collected

Question 3

mean

Answer 3

average
x̅ is mean of sample(statistic)
μ is mean of population (parameter)

Question 4

median

Answer 4

a number where as much of a list is below it as above it

1) put list in numerical order
2) determine number of observations (n)
3) determine the index(location) of the median

Question 5

mode

Answer 5

response that occurred most (highest frequency)
*cant be mode if 1 or 0
*can be tied for highest 2
2 modes-bimodel, 2+, multimodel

Question 6

numerical summary is said to be resistant if…

Answer 6

it is not affected by extreme values

Question 7

skewed left shape

Answer 7

mean

Question 8

skewed right shape

Answer 8

median

Question 9

range

Answer 9

difference between highest and lowest numbers

Question 10

standard deviation

Answer 10

how far each number in the list is from the average

Question 11

z scores

Answer 11

x-μ/σ or x-x̅/s

Question 12

percentiles

Answer 12

the kth percentile is the number where k percent of the data falls below that number (median is 50th percentile)

Question 13

Quartiles

Answer 13

pieces of data that split the data into 4 equal parts

Question 14

Q1 and Q3 are medians of

Answer 14

the lower and the upper lists receptively

*if mean is a number in the list include it in upper and lower

Question 15

Interquartile range

Answer 15

Q3-Q1

Question 16

Upper fence

Answer 16

Q3+1.5(IQR)

Question 17

Lower Fence

Answer 17

Q1-1.5(IQR)

Question 18

A piece of data is an outsider if…

Answer 18

it is outside the upper or lower fences

Question 19

Five number summary

Answer 19

list of minimum, Q1, median, Q3, and maximum (no commas)

Question 20

Box plot

Answer 20

Use numbers from 5 number summary, box is Q1, median and Q3, whiskers are up to numbers that don’t go past fence

Question 21

Shape determined by box plot

Answer 21

If line is in middle of the box its symmetric
to the left distribution is skewed right
to the right distribution is skewed left

Question 22

Scatter plot

Answer 22

a graph in which the explanatory variable is on the horizontal axis and the response variable is on the vertical axis and we plot a point for each indv. in the study

Question 23

Positive Correlation

Answer 23

↑↑ or ↓ ↓

Question 24

Negative Correlation

Answer 24

↑↓ or ↓↑

Question 25

Explanatory Variable

Answer 25

The predictor variable

Question 26

Response Variable

Answer 26

The affected variable

Question 27

r being close to 0

Answer 27

no correlation

Question 28

Residual Value

Answer 28

the difference between expected and observed values of y

Question 29

Least-Square Regression Line

Answer 29

y^b1=bo
where b1= r x sy/sx
and bo= ȳ-(b1)(x̄)

Question 30

Squared residuals

Answer 30

measure how well a line fits

Question 31

linear correlation coefficient (r)

Answer 31

r= Σ(zxi)(zyi)/n-1