general electric produces a soft white 100 watt bulb for which it states that the average life is 750 hours. Assume the deviation is 120 hours.
Suppose a consumer agency randomly selects 100 of theses bulbs and finds a sample mean life of 735 hours. should the consumer agency doubt the manufacturer's claim ?
i should first calculate z -score
my answer is -.125
please let me know if i am on the right track ?
r uthere ?
sorry i did not know
i checked my z -table and i got .45
.45 is greater than .05 so ho is true ?
i have one more question about range
Suppose scores on a national test follow a normal distribution with mean of 600 and standard deviation of 100.
What sample size would be required such that 95% of the possible sample means would be 20 points from the population mean.
explain how to calculate i am really stuck
I'm still online, but the site administrator deleted a lot of your posts - don't expect an immediate response just because we're online - often I'm working on something else or away from my computer....
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