Answer:
43%
Step-by-step explanation:
Answer:
The interval that represents the middle 68% of her commute times is between 33.5 and 42.5 minutes.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
Approximately 68% of the measures are within 1 standard deviation of the mean.
Approximately 95% of the measures are within 2 standard deviations of the mean.
Approximately 99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean of 38 minutes, standard deviation of 4.5 minutes.
Determine the interval that represents the middle 68% of her commute times.
Within 1 standard deviation of the mean. So
38 - 4.5 = 33.5 minutes
38 + 4.5 = 42.5 minutes.
The interval that represents the middle 68% of her commute times is between 33.5 and 42.5 minutes.
Answer:
n = 2b + 4
Step-by-step explanation:
4 years older = +4
2 times his brother = 2b
n= 2b+4
Answer:
option (c) n = 201
Step-by-step explanation:
Data provided in the question:
Standard deviation, s = 5.5 ounce
Confidence level = 99%
Length of confidence interval = 2 ounces
Therefore,
margin of error, E = (Length of confidence interval ) ÷ 2
= 2 ÷ 2
= 1 ounce
Now,
E = 
here,
z = 2.58 for 99% confidence interval
n = sample size
thus,
1 = 
or
n = (2.58 × 5.5)²
or
n = 201.3561 ≈ 201
Hence,
option (c) n = 201
The half life would be about 3 so making the percentage About 25%
