week 9 z-score

Question 1

what’s the percentage of approx data in the area when you +/- sd from mean

Answer 1

68%

Question 2

what percentage of scores fall between 1.96 SD away from the mean

Answer 2

95%

Question 3

what does 95% mean about extreme scores

Answer 3

extreme scores fall in 2.5% of top and bottom tails

Question 4

what does a positive z-score indicate

Answer 4

the observation is greater than the mean

Question 5

what does the values on z-score table tell you

Answer 5

the percentage of z-scores that are higher than your obtained score

Question 6

what percentage of scores are within +/-2.58 SDs of the mean

Answer 6

99%

Question 7

confidence intervals

Answer 7

to identify the limits in which we have a specified level of confidence that a randomly selected score in the distribution will fall b/t a specified range

Question 8

2 most useful confidence intervals

Answer 8

95% (+/-1.96) and 99% (2.58)

Question 9

what are 2 things you can do when you have extreme outliers

Answer 9

1. remove it from data
2. change the extreme score

Question 10

2 ways of changing the extreme outlier

Answer 10

1. Replace with the Next Highest Score Plus One Unit

Find the next highest value in your dataset (excluding the outlier), and replace the outlier with that value plus one unit of change.
This maintains the dataset’s range while reducing the outlier’s influence.

2.Replace with Mean Plus 2 Standard Deviations

Replace the outlier with
mean+2×SD

This is based on the assumption that approximately 95% of data in a normal distribution falls within ±2 SD from the mean.
This method keeps the outlier closer to the range of the majority of the data.