Question

1.

A clinical trial was conducted to determine if a certain type of inoculation has an effect on the incidence of a certain disease. The incident rate is known to be 0.20. 500 of the rats were given the inoculation. 98 of the rats contracted it. At the α = 0.05 level of significance, is there evidence to conclude that the incidence rates for the rats inoculated is different than 0.20? Follow the steps in a hypothesis test using ALL possible methods to determine significance (p-value, standardized statistic, and confidence interval). What type of error could have been made?

2.

A colleague went to the lego.com website in February 2014 and recorded the number of pieces and the sales price for 150 Lego products listed there. The fitted line is given by ?̂=4.862+0.105?, and values of the dataset range from 35 to 3,500.
• Given this fitted regression model, what is the range of possible values for the correlation coefficient?
• What is the predicted sale price of a Lego product that weighs has 2000 pieces?
• What is the predicted sale price of a Lego product that weighs has 10 pieces?
• Which prediction are you more confident in? Explain.

Answer 1

1

2.

r^2 = 0.949 and r = 0.974

the predicted sale price of a Lego product that weighs has 2000 pieces

?̂=4.862+0.105?

predicted price = 4.862+0.105 * 2000 = 214.862

the predicted sale price of a Lego product that weighs has 10 pieces

?̂=4.862+0.105?

predicted price = 4.862+0.105 * 10 = 5.912

the predicted sale price of a Lego product that weighs has 10 pieces is 5.912 is more confident in

because less pieces more profit ( ex. 2000 has 200 10's so price = 200*5.912 = 1182.4 > 214.86 )