A cell phone company orders 500 new phones from a manufacturer. If the probability of a phone being defective is 2.9%, predict h
2 answers:
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Answer:
option (a) It will be closer to 30 than to 20
Step-by-step explanation:
Data provided in the question:
For sample 1:
n₁ = 10
variance, s₁² = 20
For sample 2:
n₂ = 15
variance, s₂² = 30
Now,
The pooled variance is calculated using the formula,
on substituting the given respective values, we get
or
= 26.0869
Hence,
the pooled variance will be closer to 30 than to 20
Therefore,
The correct answer is option (a) It will be closer to 30 than to 20
Using the t-distribution, it is found that since the <u>test statistic is greater than the critical value for the right-tailed test</u>, it is found that there is enough evidence to conclude that Battery B outlasts Battery A by more than 2 hours.
At the null hypothesis, it is <u>tested if it does not outlast by more than 2 hours</u>, that is, the subtraction is not more than 2:
At the alternative hypothesis, it is <u>tested if it outlasts by more than 2 hours</u>, that is:
- The sample means are:
- The standard deviations for the samples are
Hence, the standard errors are:
The distribution of the difference has <u>mean and standard deviation</u> given by:
The test statistic is given by:
In which is the value tested at the hypothesis.
Hence:
The critical value for a <u>right-tailed test</u>, as we are testing if the subtraction is greater than a value, with a <u>0.05 significance level</u> and 12 + 12 - 2 = <u>22 df</u> is given by
Since the <u>test statistic is greater than the critical value for the right-tailed test</u>, it is found that there is enough evidence to conclude that Battery B outlasts Battery A by more than 2 hours.
A similar problem is given at brainly.com/question/13873630