Question

Question 3 1 pts Two different types of injection-molding machines are used to form plastic parts. A part is considered defective if it has excessive shrinkage or is discolored. Two random samples, each of size 300, are selected and 15 defective parts are found in the sample from machine 1 and 8 defective parts are found in the sample from machine 2. What type of hypothesis test should you use to determine if both machines produce the same fraction of defective parts? 2 Sample Z-Test O 2 Sample Prop Z-Test O 2 Sample Prop T-Test Paired T-Test Question 4 1 pts In a series of tests to study the efficacy of ginkgo biloba on memory, Solomon et al. first looked at differences in memory tests of people six weeks before and after joining the study ["Ginkgo for Memory Enhancement: A Randomized Controlled Trial", 2002]. For 99 patients receiving no medication, the average increase in category fluency (number of words generated in one minute) was 1.07 words with a standard deviation of 3.195 words. Researchers wanted to know whether the mean number of words recalled was positive. What type of hypothesis test should be used for this problem? Paired T-Test 2 Sample T-Test 2 Sample Z-Test Chi square Test

Answer 1

Ans:

1)

Correct option is:

2 sample Prop Z test

As,we are comparing two sample proportions,so we use will use 2 sample proportion z test.

2)

Correct option is:

paired t test

As,we are comparing the same subject at different times,so we will us paired t test.