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In the computer game World of Warcraft, some of the strikes are critical strikes

ID: 3246894 • Letter: I

Question

In the computer game World of Warcraft, some of the strikes are critical strikes, which do more damage. Assume that the probability of a critical strike is the same for every attack, and that attacks are independent. During a particular fight, a character has 211 critical strikes out of 746 attacks. What is the lower bound for the 99% confidence interval for the proportion of strikes that are critical strikes. Round to three decimal places (for example: 0.419). Write only a number as your answer. Your Answer: Answer

Explanation / Answer

We can used one sample proportion z test.

Using minitab.

The command for one sample proportion z test in minitab is

Stat>>>Basic statistics>>>1-proportion...

Then click on summarized data

number of events = x = 211

Number of trials = n = 746

then click on option

Level of confidence in percentage = c = ( 1- lpha)*100 = = (1 -0.05)*100 = 99.0

so put "Confidence level " = 99.0

Alternative = not equal

then click on "Use test and interval based on normal approximation"

Then click on OK and again click on OK

So we get the following output

MTB > POne 746 211;
SUBC>   Confidence 99;
SUBC>   UseZ.

Test and CI for One Proportion

Sample    X    N    Sample p         99% CI
1         211 746 0.282842 (0.240367, 0.325316)

Using the normal approximation.

Lower limit for 99% confidence interval for proportion of strikes that are critical strikes = 0.240