<span>204
First, lookup a standard normal table and see what the z-score is for 0.025 (one half of 100% - 95%) to allow for equal sized tails. You should find that the z-score is 1.96. That means that 95% of the time, the value should be within 1.96 standard deviations of the mean. Now let's calculate the standard deviation.
800 is 800 - 1200 = -400 to the left of the mean of 1200.
1600 is 1600 - 1200 = 400 to the right of the mean of 1200.
So we are an equal distance of 400 on both sides of the mean. And we know from the z-score of 1.96, that we're 1.96 standard deviations from the mean. So a little division will give us the standard deviation. Which is:
400 / 1.96 = 204.0816327
So the standard deviation of the light bulbs is 204</span>
Answer:
s > 200
Step-by-step explanation:
Note that
> means greater than
< means less than
for example : 2 < 3 means 2 is less than 3
3 >2 means 3 is greater than 2
If he needs to sell more than 200, sales has to be greater than 200 = s > 200
This probability is the same as 1-(two different suited cards). Your first card can be any of the 52 cards. Your second card must be any of the 39 different suited remaining 51 cards. So the answer is 1 - (52/52)(39-51). Note: I assumed there was no replacement.
