A major appliance store is considering introducing an online shopping service. The service will be implemented if more than 40% of Internet users purchase through this medium. 300 users were interviewed and 170 indicated that they use the Internet to make purchases. With a significance of 0.13, do the data indicate that the service should be implemented?
Question
Answer:
To determine whether the data indicate that the service should be implemented, we can perform a hypothesis test using the given information. In this case, we'll use a hypothesis test for a population proportion. Here are the steps:
Step 1: Set up Hypotheses
The null hypothesis (H0) is that the proportion of Internet users who purchase through the online shopping service is less than or equal to 40%:
H0: p β€ 0.40
The alternative hypothesis (Ha) is that the proportion is greater than 40%:
Ha: p > 0.40
Step 2: Collect Data
From the information given:
Number of Internet users surveyed (n) = 300
Number of users who indicated they use the Internet to make purchases (x) = 170
Step 3: Choose a Significance Level
The significance level (alpha) is given as 0.13. This is the probability of making a Type I error, which is the probability of rejecting the null hypothesis when it is actually true.
Step 4: Calculate the Test Statistic
We will calculate the test statistic using the sample proportion (pΜ) and the null hypothesis proportion (p0):
pΜ = x / n = 170 / 300 = 0.5667
Now, we calculate the standard error (SE) of the sample proportion:
SE = sqrt((p0 * (1 - p0)) / n)
SE = sqrt((0.40 * 0.60) / 300) β 0.0283
Now, we can calculate the z-score:
z = (pΜ - p0) / SE = (0.5667 - 0.40) / 0.0693 β 5.8905
Step 5: Determine the Critical Value
Since we have a significance level of 0.13 and this is a one-tailed test (greater than), we need to find the critical z-value from the standard normal distribution. You can use a standard normal table or calculator to find the z-value corresponding to a cumulative probability of 1 - 0.13 = 0.87.
For a significance level of 0.13, the critical z-value is approximately 1.1503.
Step 6: Make a Decision
Compare the calculated z-value (5.8905) to the critical z-value (1.1503).
Since the calculated z-value (5.8905) is greater than the critical z-value (1.1503), we reject the null hypothesis (H0).
Step 7: Conclusion
Since we have rejected the null hypothesis, we have evidence to suggest that more than 40% of Internet users purchase through the online shopping service. Therefore, based on the data and the significance level of 0.13, it appears that the service should be implemented.
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