The average life of light bulbs produced by SABA Electric Co. is expected to be
ID: 3310333 • Letter: T
Question
The average life of light bulbs produced by SABA Electric Co. is expected to be normally distributed with the mean service life of 950 hours and standard deviation of 100 hours. A random sample of 100 bulbs is tested and it has a mean life of 910 hours. Can researcher conclude that the mean service life of the bulbs is less than the expectation? H0 is null hypothesis, and Ha is alternative hypothesis. Which one of the following is a correct conclusion based on the given data?
A. Reject H0. The mean service life of the bulbs is less than the expectation.
B. Do not reject H0. The mean service life of the bulbs is less than the expectation.
C. Reject H0. The mean service life of the bulbs is not less than the expectation
D. Do not reject H0. The mean service life of the bulbs is not less than the expectation
E. None of the above.
Explanation / Answer
The statistical software output for this problem is:
One sample Z summary hypothesis test:
: Mean of population
H0 : = 950
HA : < 950
Standard deviation = 100
Hypothesis test results:
Since p - value is very small , we reject the null hypothesis.
Hence,
Reject H0. The mean service life of the bulbs is less than the expectation.
Option A is correct.
Mean n Sample Mean Std. Err. Z-Stat P-value 100 910 10 -4 <0.0001Related Questions
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