Originally Posted by

**Dybbuk** Hello,

I've lost my revision notes for an exam tomorrow (I know, I know!) and I was hoping someone could help me with the following:

1. deduce the population mean (u)

2. demonstrate how to carry out a hypothesis test at the 0.95 probability level as to whether population mean is greater than 80.

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This is for grouped data, and I have the following info:

n = 207

Arithmetic mean = 86.64

Median = 79.02

Standard deviation = 24.38

Co-efficient of variation = 28.14

Ql = 69.69

Qu = 102.92

Interquartile range = 86.31

Skewness = 0.94

sum of fx' = 17935

sum of fx'² = 1676975

Can anyone help??