A gun-like apparatus has recently been designed to replace needles in administering vaccines. The apparatus can be set to inject different amounts of the serum, but because of random fluctuations the actual amount injected is normally distributed with a mean equal to the setting and with an unknown variance 2. It has been decided that the apparatus would be too dangerous to use if exceeds .10. If a random sample of 50 injections resulted in a sample standard deviation of .08, should use of the new apparatus be discontinued? Suppose the level of significance is = .10. Comment on the appropriate choice of a significance level for this problem, as well as the appropriate choice of the null hypothesis.

Stat notes 2 Categorical data= nominal and ordinal Quantitative data= discrete and continuous Relative frequency table- all #’s in table sum to 1 for percentages Proportion= # in category/ total sample size (risk is the same thing as proportion) How do you know which variable is the response and which is the explanatory Rows= response variable Columns= explanatory variable How do we compare the risks of two different groups By using relative risk - If relative risk is less than, first group has a smaller risk - Odds- ratio of counts of the two levels of one categorical variable haves/have nots Proportion for a sample- p (hat) Proportion for population- P Two-way table- used to show the relationship between two categorical variables Two categorical variables: -