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A manufacturer claims that its rechargeable batteries are good for an average of more than 1.000 charges. A random sample of 100 batteries has a mean life of 1002 charges and a standard deviation of 14. Is there enough evidence to support this claim at a significance level of 0.01?

a. State the hypotheses.
b. State the test statistie information
c. State either the p-value or the critical information d. State your conclusion and explain your reasoning

2 Answers

1 vote

Final answer:

The test statistic does not exceed the critical value, thus we cannot reject the null hypothesis at the 0.01 significance level, indicating that there is insufficient evidence to support the manufacturer's claim.

Step-by-step explanation:

Hypothesis Testing for Battery Charges

To determine if there is enough evidence to support the manufacturer's claim that its rechargeable batteries are good for an average of more than 1000 charges, we conduct a hypothesis test at the 0.01 significance level.

a. State the hypotheses

The null hypothesis (H0): μ ≤ 1000 (The average number of charges is 1000 or fewer.)

The alternative hypothesis (H1): μ > 1000 (The average number of charges is greater than 1000.)

b. State the test statistic information

The test statistic is calculated using the formula for the z-score, which is (sample mean - population mean) / (standard deviation / sqrt(sample size)). Substituting the given values: (1002 - 1000) / (14 / sqrt(100)) = 2 / (14 / 10) = 1.43.

c. State either the p-value or the critical value

Since the significance level is 0.01, the corresponding critical z-value is approximately 2.33. But our test statistic is 1.43, which is less than the critical value.

d. State your conclusion and explain your reasoning

Because the test statistic does not exceed the critical value, we do not reject the null hypothesis. Therefore, there is not enough statistical evidence at the 0.01 significance level to support the manufacturer's claim that batteries are good for more than 1000 charges.

User Peter Marks
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4.7k points
4 votes

It's 1000 charges and not 1.000 charges

Answer:

A)Null Hypothesis;H0: μ = 1000

Alternative Hypothesis;Ha: μ ≠ 1000

B) t-statistic = 1.4286

C) p-value = 0.15628

D) We conclude that we will fail to reject the manufacturers claim that its rechargeable batteries are good for an average of more than 1000 charges

Step-by-step explanation:

We are given;

x = 1002 charges

s = 14

μ = 1000 charges

n = 100

degree of freedom = n - 1 = 100 - 1 = 99

A) The hypotheses are;

Null Hypothesis;H0: μ = 1000

Alternative Hypothesis;Ha: μ ≠ 1000

B) t-statistic = (x - μ)/(s/√n)

(1002 - 1000)/(14/√100) = 1.4286

C) From the t-score calculator results attached, the p-value is approximately 0.15628

D) The P-value of 0.15628 is is greater than the significance level of 0.01, thus we fail to reject the null hypothesis, and we conclude that the result is statistically nonsignificant.

A manufacturer claims that its rechargeable batteries are good for an average of more-example-1
User Makhdumi
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4.5k points