Please help whats the last meter on 10 will mark brainliest!
1 answer:
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Answer: c. z = 1.35; Reject the null hypothesis
Step-by-step explanation:
Let be the average life expectancy of its batteries.
As per given , we have
Null hypothesis :
Alternative hypothesis :
Since is right-tailed and population standard deviation is also known, so we perform right-tailed z-test.
Test statistic :
where, n= sample size
= sample mean
= Population mean
=population standard deviation
For , we have
Critical one-tailed test value for 0.10 significance level :
Decision : Since critical z value (1.28) < test statistic (1.35), so we reject the null hypothesis .
[When critical value is less than the test statistic value , we reject the null hypothesis .]
Since we know that 1/4 is equal to 25%, or 0.25 in decimal form, we are able to work with 0.75 in the expression.
We are told to use j as the original price of the jeans, so we can set up the expression:
to represent the cost of the jeans with the discount.
Then to simplify, we simply take out j as a common factor, and solve what's in the parentheses:
or
Using this equation, we can solve for the b part of the question. If the pair of jeans originally costs $60, plug in 60 to where j is in the expression:
Therefore, the cost of the jeans after the discount is C) $45.