Normal distribution and estimation statistics

Question 1

If the distribution is skewed, would you use mean, median or mode?

Answer 1

Median

Question 2

Why do we want our data to be normally distributed?

Answer 2

Most statistical tests require it

It allows us to make predictions about data/make assumptions beyond sample data

Question 3

What is needed to calculate the normal distribution?

Answer 3

Mean and standard deviation

Question 4

How many SD is 95% probability? 99%?

Answer 4

2. 3.

Question 5

How can you assess normality?

Answer 5

Visual assessment
Kurtosis/skewness within 1
Mean/median similar
Statistical tests

Question 6

How do you calculate z-score?

Answer 6

(observed value - total mean) / standard deviation of sample

Question 7

What is the z-score of 95% confidence? 99%?

Answer 7

1.96. 2.58.

Question 8

How do you calculate standard error?

Answer 8

sd/sq.rt (pop.size)

Question 9

How do you calculate margin of error?

Answer 9

z-score x SE

e.g. 1.96 x SE

Question 10

How do you calculate confidence intervals?

Answer 10

(mean-MoE) - (mean+MoE)