shapes and distributions: z scores

Question 1

how do we move out on SD from the mean; what % of data is this

Answer 1

mean + SD and mean - SD; 68%

Question 2

what is a Z score

Answer 2

distance of score from mean measured in SD

Question 3

Is the SD In the Z score formula sample of population SD

Answer 3

sample u eejit

Question 4

what 2 things does a Z score tell us about that particular score

Answer 4

how extreme is in comparison to others

how many scores are greater/less than it

Question 5

what do we do instead of calculating the whole standard normal distribution for our data

Answer 5

calculate a single Z score for one score in data depending on what want to know abt our distribution

Question 6

what does . a big variation mean

Answer 6

score relatively close to mean

Question 7

what does a small variation mean

Answer 7

score in same place is far from mean

Question 8

what does the probability of several shaded areas equal

Answer 8

sum of prob of shaded areas

Question 9

how do we obtain probability of obtaining scores greater than the absolute value of several Z scores

Answer 9

add shaded areas

Question 10

how calculate probability non shaded areas

Answer 10

1- prob shaded

Question 11

what does looking up score in Z score table tell us

Answer 11

proportion of scores larger than score and therefore scores smaller too

Question 12

probability that a randomly selected value in the distribution will fall btwn two Z-scores?

Answer 12

calculare z scores for each of 2 values, then find percentage greater than each score
then take away those numbers and voila bitches

Question 13

where are 99% of scores

Answer 13

within +-2.58 SDs of the mean

Question 14

how do you set probable limits/ confidence intervals

Answer 14

identify limits in which specified level of confidence that randomly selected score in distrib will fall within specified range

Question 15

what are limits set to for probable limits/ confidence intervals

Answer 15

95% and 99%

have Z score so then find X

Question 16

what is the equation for the confidence intervals and what must you remember to do

Answer 16

X = M ± Zcritical(SD)

Compute one value of X when Z is positive and one value of X when Z is negative and this will give us our range

Question 17

how do you correct outliers

Answer 17

remove or change the score

Question 18

how do you change the outlier

Answer 18

replace with next highest score +1

replace with mean +-2 xSD but only if remains highest/lowest score