You times it by one and then add the two zeros so your answer is 3,500
29 + (-37) = 29 - 37
answer is C. 29 - 37
She missed 3 questions,
11/100 equals x/26
^set up this proportion
you get 286 equals 100x
and x equals 2.86
round this to 3 questions
to check your work, do 23/26
Answer:
1,082
Step-by-step explanation:
The sample size n in Simple Random Sampling is given by
where
z = 1.645 is the critical value for a 90% confidence level (*)
s = 2 is the estimated population standard deviation
e = 0.1 mm points is the margin of error
so
rounded up to the nearest integer.
So the manufacturer should test 1,083 parts.
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(*)This is a point z such that the area under the Normal curve N(0,1) outside the interval [-z, z] equals 10% = 0.1
It can be obtained in Excel with
NORMINV(1-0.05,0,1)
and in OpenOffice Calc with
NORMINV(1-0.05;0;1)
Answer: 68% of light bulbs last between 1765 hours and 1835 hours.
Step-by-step explanation:
The empirical rule states that for a normal distribution, nearly all of the data will fall within three standard deviations of the mean . The empirical rule is further illustrated below
68% of data falls within the first standard deviation from the mean.
95% fall within two standard deviations.
99.7% fall within three standard deviations.
From the information given, the mean is 1800 hours and the standard deviation is 35 hours.
1 standard deviation = 1 × 35 = 35
1800 - 35 = 1765 hours
1800 + 35 = 1835 hours
Therefore, 68% of light bulbs last between 1765 hours and 1835 hours.
