Week 7 - Z Test and Normality

Question 1

When is the Z test used?

Answer 1

Continuous Data

N = 1

Question 2

Normality and outlier check?

Answer 2

No

Question 2

How does the test differ is it is a two tailed test?

Answer 2

For a TWO TAILED TEST - multiply the P value by 2

Question 2

What does a -ve and a +ve Z score indicate

Answer 2

-ve Z score –> observation is below average

+ve Z score –> observation is above average

*For converting Z score to P value - ignore the sign

Question 3

When is there significance?

Answer 3

When the P value is LESS THAN 0.05

Question 3

What if there is no exact corresponding p value?

Answer 3

Round DOWN to the nearest value

Question 4

EDA: Normality - how do you check for normality

Answer 4

1. Create roughly N/4 equal sized bins
2. Tally for each value within each bin
3. Check normality - scores should be most common in the middle bin