Two urns contain white balls and yellow balls. The first urn contains 7 white balls and 7 yellow balls and the second urn contai
1 answer:
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Answer:
4
Step-by-step explanation:
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Answer:
129.3 in²
Step-by-step explanation:
The shaded segment is calculated as
area of sector ABC - area of triangle ABC
area of sector = area of circle × fraction of circle
A = πr² ×
= π × 18² ×
= 324π × = 54π in²
area of Δ ABC = × 18 × 18 × sin60° ≈ 40.30 in²
Then
shaded area = 54π - 40.30 ≈ 129.3 in² ( to the nearest tenth )
Answer:
There is enough evidence to support the claim that the batteries power the laptops for significantly less than 4 hours. (P-value = 0).
The null and alternative hypothesis are:
Step-by-step explanation:
<em>The question is incomplete: To test this claim a sample or population standard deviation is needed.</em>
<em>We will estimate that the sample standard deviation is 2 hours, and use a t-test to test that claim.</em>
<em> NOTE (after solving): The difference between the sample mean and the mean of the null hypothesis is big enough to reject the null hypothesis, even when we have a sample standard deviation of 3.5 hours, which can be considered bigger than the maximum standard deviation for the sample.</em>
This is a hypothesis test for the population mean.
The claim is that the batteries power the laptops for significantly less than 4 hours.
Then, the null and alternative hypothesis are:
The significance level is 0.05.
The sample has a size n=500.
The sample mean is M=3.5.
As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=2.
The estimated standard error of the mean is computed using the formula:
Then, we can calculate the t-statistic as:
The degrees of freedom for this sample size are:
This test is a left-tailed test, with 499 degrees of freedom and t=-5.5902, so the P-value for this test is calculated as (using a t-table):
As the P-value (0) is smaller than the significance level (0.05), the effect is significant.
The null hypothesis is rejected.
There is enough evidence to support the claim that the batteries power the laptops for significantly less than 4 hours.