Question

Identify the conclusion in a hypothesis test of the following claim and sample data:

Claim: "The average battery life (between charges) of this model of tablet is at least 12 hours."
A random sample of 80 of these tablets is selected, and it is found that their average battery life is 11.58 hours with a standard deviation of 1.93 hours. Test the claim at the 0.05 significance level.
a. There is not sufficient evidence to warrant rejection of the claim.
b. There is sufficient evidence to warrant rejection of the claim.
c. There is sufficient evidence to support the claim.
d. There is not sufficient evidence to support the claim.

Answer 1

C

Explanation:

Firstly, we set up the null and alternative hypothesis as follows;

The null hypothesis is;

H0: μ ≥ 12

The alternative hypothesis is;

Ha : μ < 12

Next step is to calculate the test statistic z

Mathematically;

z = (x - μ )/ σ /√n

= (11.58 - 12) /1.93/√(80

Test statistic z = -1.92

Now we proceed to find the probability value that is equal to the value of the test statistic. We can find this by using the standard normal table or NORMSTD function on excel

P(z < -1.92) = 0.0274

P-value = 0.0274

alpha = 0.05

From the above, we can see that

P-value < alpha

And because of this, we are going to reject the null hypothesis and therefore accept the alternative.

We then conclude that there is sufficient evidence to conclude that "The average battery life (between charges) of this model of tablet is at least 12 hours."