Variations in population

Question 1

What is true about a normal distribution curve?

Answer 1

• The normal distribution is symmetric about its mean
• The greatest frequency of observations occurs at the mean value
• The curve is ‘bell shaped’
• The sd, σ =how broad the bell shape is
• The highest point on the curve is the mean, median and mode of the distribution

Question 2

What is the total area under a normal distribution curve defined as?

Answer 2

1

Question 3

On packaging what does the ‘e’ mark guarantee?

Answer 3

1. The actual contents of the packages shall not be less, on average, than the nominal quantity.
2. Not more than 2.5 per cent of packages may be non-standard i.e. have Tolerable Negative Errors (TNE) greater than that specified for the particular nominal quantity.
3. No package may be inadequate, i.e. be deficient by more than twice the TNE.