A telephone directory contains 50000 names. A researcher wishes to select a systematic sample of 100 names from the directory.
Explain in detail how the researcher should obtain such a sample.
Give one advantage and one disadvantage of
quota sampling,
systematic sampling.
The heights of a random sample of 10 imported orchids are measured. The mean height of the sample is found to be 20.1 cm . The heights of the orchids are normally distributed.
Given that the population standard deviation is 0.5 cm ,
estimate limits between which \(95 \%\) of the heights of the orchids lie,
find a 98\% confidence interval for the mean height of the orchids.
A grower claims that the mean height of this type of orchid is 19.5 cm .
Comment on the grower's claim. Give a reason for your answer.