statistics

Question 1

what does the mean stand for and the symbol it uses

Answer 1

its the average of all values together then divided by how many values there

the symbol is the x bar line on top or fancy M

Question 2

what does median stand for

Answer 2

middle values (arranged least to greatest then middle values) - if no middle and even amount number take average of middle values

Question 3

what does the mode stand for

Answer 3

its the value that occurs the most often

Question 4

what does the range stand for

Answer 4

the difference between largest / smallest values (sub largest from smallest)

Question 5

what does standard deviation stand for

Answer 5

how much each value ges up/down from the mean and spread of data
- low # of sd shows more consistant
- high # sd shows less consistant

Question 6

how to calculate mean / standard deviation when no frequency

Answer 6

-stat then 1
-edit and put values into L1
-then stat move over to calc
-then press 1 and enter

Question 7

how to calculate mean / standard deviation when theres a frequency value

Answer 7

-stat then 1
-edit and put values into L1 and L2
-then press 2nd mode and calc
-push 1 and 2nd 1 then , 2nd 2
-enter

Question 8

when finding the mode / sd what do you do if info just gives - in between 2 numbers

Answer 8

you have to take the average of them first

Question 9

how to check something has normal distribution

Answer 9

-see if mean / median close
-when using the x graph method see if resembles curve
- see if data should be similer to what would be in one standard deviation

Question 10

all values of data above the mean have what type of z score

Answer 10

positive

Question 11

all values of data belloe the mean have what type of z score

Answer 11

negative

Question 12

higher sd stand for what type of consistancy

Answer 12

lower consistancy because more high so means each time is farther away from mean less consis

Question 13

lower stand deviation for what type of consistancy

Answer 13

it stands for being more consistant and is closser mean so more consistant

Question 14

when do you use to calculate the z-score

Answer 14

formula) when you have 3 values you can re-arrange and solve for z score then use it to find percent ect
z= x - M / sd

Question 15

when things go into the z-score what similarities do they MUST have

Answer 15

they must all be the same units
ex) all number of bottles or all comparing ml

Question 16

how to find percent when given a z-score

Answer 16

• determine if its a neg bellow or above the mean
• go to chart for either pos or neg then the side up and down is the first values of z score the side to side is the last value z score
• then times by 100
  (when looking for % and values are the same dstance apart then get average)

Question 17

how to find z score from percent

Answer 17

• see if neg or pos go to that chart
• look for the % then times by 100 then look and the up and down values that make it first values then side to side values that make up last values

Question 18

when asking for % to the left given z-score

Answer 18

1) if not given z score and trying to look for % first use formula to find z-score
2) after having z-score then look on chart to find the %

Question 19

what to do when asking for % thats in-between 2 values

Answer 19

1) find z score from formula or if given
2) then use z-chart to find % for both z scores
3) then subtract the %’s to get middle value

Question 20

what to do when asking for the % to the right

Answer 20

1) find z-score if not given by formula
2) then find %
3) subtract 100 from percent given

Question 21

whenever question asking how many of other unit when having a percent how do you find how much

Answer 21

then turn % to dec divide by 100 times by other value

Question 22

when looking for a data values percent and its on the graph already and isnt in-between any lines ect how do you find %

Answer 22

you would go off referance formula sheet and add up the % in the colums that would be shaded

Question 23

when the confidence level increases what happens to the margin of error

Answer 23

the margin of error increases bc confidence level increases bc large margin of error is bigger range and easier to be confident with bigger range

Question 24

when someone wants to be more confident in the results what must they do to increase it

Answer 24

take more samples because within more people you can be more sure that its the correct information

Question 25

when theres a large same size what decreases

Answer 25

the margin of error decreases when higher confidence level and larger sample size

Question 26

when solved for z-score and corresponding % and looking for spefific value on x axis how to find

Answer 26

use the formula to solve for x