CHAPTER 8

Question 1

What is a probability distribution?

Answer 1

• a list of all possible outcomes together with their probabilities

Question 2

what is the notation for binomial distribution?

Answer 2

• B(n, p)
• n= trials
• p= probability of success

Question 3

conditions needed for a binomial distribution:

Answer 3

• fixed number of trials
• trials are independent
• two possible outcomes for each trial (success and failure)

Question 4

probabilities for binomial distribution expansion:

Answer 4

(p + q) ^n
p= success
q= failure
n= trials

Question 5

what is the mean of binomial distribution?

Answer 5

np

Question 6

what do the coefficients of a binomial expansion follow?

Answer 6

• follow the pattern of Pascal’s triangle

Question 7

how can you find the coefficients of a binomial expansion?

Answer 7

• using the nCr button on a calculator

Question 8

what does a normal distribution look like?

Answer 8

• bell shaped

Question 9

conditions needed for a normal distribution:

Answer 9

• data is continuous
• distribution is symmetrical and bell- shaped
• the mode, median and mean are approximately equal

Question 10

notation for normal distribution:

Answer 10

N( u(mew), o^2)
u (mew)= mean
o^2= variance

Question 11

standardised score equation:

Answer 11

score- mean/ standard deviation

Question 12

what is quality assurance?

Answer 12

• involves checking samples to ensure that the product of a manufacturing process meets the required standard

Question 13

what can you construct if you take samples at regular intervals?

Answer 13

• control charts

Question 14

what is a control chart?

Answer 14

• a time series chart that is used for quality assurance

Question 15

where are warning limits set?

Answer 15

u (mew) ±2o (o with line)

Question 16

where are action limits usually set?

Answer 16

u (mew) +_ 3o (o with line)
- if the sample mean is between the action and warning limits then another sample is taken immediately to see if there might be a problem
- if a sample mean is outside the action limits the process is stopped and the machinery is reset

Question 17

important properties of a normal distribution:

Answer 17

• 68% of observations lie within +_ one standard deviation of the mean
• 95% of observation lie within +_ two standard deviations from the mean
• 99.8% of observations lie within +_ three standard deviations of the mean

Question 18

what is the variance of a normal distribution?

Answer 18

• a measure of how spread the data is
• variance= (standard deviation)^2