Answer:
95%.
Step-by-step explanation:
We have been given that the lifetimes of light bulbs of a particular type are normally distributed with a mean of 370 hours and a standard deviation of 7 hours.
We are asked to find the percentage of the bulbs whose lifetimes lie within 2 standard deviations to either side of the mean using empirical rule.
The empirical rule (68-95-99.7) states that approximately 68% of data points lie within 1 standard deviation of mean and 95% of data points lie within two standard deviation of mean. 99.7% of data points lie within three standard deviation of mean.
Therefore, approximately 95% of data points lie within two standard deviation of mean.
Subtract to find the difference:
2000 - 500 = 1500
Divide the difference by the original population:
1500 / 500 = 3
Multiply that by 100 to get the percentage:
3 x 100 = 300%
Answer:
to complete the square, you add (b/2)^2 on both side. in this case, b is -6, half of -6 is -3, -3 squared is 9, so:
x^2-6x+9=-13+9
(x-3)^2=-4
This quadratic equation have unreal solutions
Step-by-step explanation:
Answer: d
Step-by-step explanation:
i think that's the answer sorry if i'm wrong
Answer:
x=146
Step-by-step explanation:
I hope this helps
