Normal Distribution

Question 1

How do you represent normally distributed data?

Answer 1

Question 2

What are the characteristics of the normally distributed curve?

Answer 2

Symmetrical
Continuous
Mode= median= mean
Total area under curve = 1

Question 3

What percentage of the data is within 1 standard deviation, 2 and 3?

Answer 3

1. 68%
2. 95%
3. 99.7%

Question 4

What is the formula for standardising X results ?

Answer 4

Where Z has a mean of zero and standard deviation of 1

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Question 11

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Question 12

What does the letter Z represent?

Answer 12

The number of standard deviations above the mean.

The variable is known as a standard normal distribution

Question 13

What is the formula for Z coding?

Answer 13

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Question 18

What happens to the standard deviation and variance increasing by a scale factor 3?

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Question 22

What’s the general method ?

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Question 26

What are the assumptions/ conditions for normal distribution?

Answer 26

When p is close to 0.5 and n is fairly large it resembles normal distribution

Question 27

Why use a normal approximation for binomial distribution?

Answer 27

The binomial formula makes use of factorials which is not very efficient unless computed

Question 28

How do you convert from binomial distribution to normal distribution?

Answer 28

Question 29

What is continuity correction? (And steps to do so)

Answer 29

Approximating a discrete range using a continuous one
1. If > or < convert to <=, >= first
2. Enlarge the range at each end by 0.5

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Question 31

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Question 34

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