Answer: in 95% of races, his finishing time will be between 62 and 64 seconds.
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 63 seconds and the standard deviation is 5 seconds.
2 standard deviations = 2 × 0.5 = 1
63 - 1 = 62 seconds
63 + 1 = 64 seconds
Therefore, in 95% of races, his finishing time will be between 62 and 64 seconds.
Answer:
a) 
=0.89
b) 0.8413
Step-by-step explanation:
we know that
x - N(150, 20^2)
check
Answer:
see the explanation
Step-by-step explanation:
Remember that
A proportion is the ratio (quotient) between two numbers
so
Twelve hundredths to three is ----> 
Twenty-four hundredths to eight ----> 
therefore
Twelve hundredths is to three as twenty-four hundredths is to eight
Note The proportion is not true
2x + y = 0
2x + 3 = 0
- 3 - 3
2x = -3
2 2
x = -1¹/₂
(x, y) = (-1¹/₂, 3)
2x1,000,000
9x100,000
3x10,000
7x1,000
0x100
8x10
2x1
