# Statistics Problems

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The bank sets up an experiment to test the effectiveness of the DVD. The mail it out to a random sample of delinquent customers and keep track of how many actually do contact the bank to arrange payments. The bank's statistician calculates a p-value (probability-value) of 0.003.

1. What does this p-value suggest about the effectiveness of the DVD?

A) This is low p-value which leads us to reject the null hypothesis and conclude that the DVD is more effective than sending a letter.
B) This is low p-value which leads us to reject the null hypothesis and we cannot conclude that the DVD is more effective than sending a letter.
C) This is not a low p-value so we fail to reject the null hypothesis and conclude that the DVD is more effective than sending a letter.
D) This is not a low p-value so we reject the null hypothesis and conclude that the DVD is more effective than sending a letter.
E) The p-value is not helpful in making a decision.

2. What additional information might be helpful in making the decision about the effectiveness of the DVD?

A) The results are very clear so no additional information is needed.
B) A confidence interval would be helpful since we can only state that the proportion of delinquent customers who pay after getting the DVD is greater than 30%.
C) The bank statistician should recalculate the p-value since it is probably incorrect.
D) A confidence interval would be helpful since we can only state that the proportion of delinquent customers who pay after getting the DVD is less than 30%.

• Statistics Problems - ,

A market sells potatoes whose weights are normally distributed with mean 65 grams and standard deviation 15 grams.
(i) Find the probability that a randomly chosen potato weighs between 40 grams and 80 grams.
The market sells potatoes weighing more than 80 grams separately packaged. Potatoes weighing between 80 grams and L grams are labeled large and potatoes weighing over L grams are labeled as extra-large.
(ii) Given that a randomly chosen potato is twice as likely to be large as extra-large, calculate the value of L. A market sells potatoes whose weights are normally distributed with mean 65 grams and standard deviation 15 grams.

• Statistics Problems - ,

i) 0.7937
ii) .8