Answer:
The correct option is b. approximately 68% of the data falls within 1 standard deviation (+-1) of the mean
Explanation:
According to the empirical rule of normal distribution:
1. Approximately 68% of the data falls within 1 standard deviation 
of the mean
2. Approximately 95% of the data falls within 2 standard deviations 
of the mean
3. Approximately 99.7% of the data falls within 3 standard deviations 
of the mean.
Therefore, among the given options, only option b adheres to the empirical rule of the normal distribution. Therefore, the option b is correct
I know they are but i’m not sure why.
Answer:
The 95% confidence interval would be given by (0.175;0.225)
Step-by-step explanation:
Assuming this question: In a survey of 1000 US adults, twenty percent say they never exercise. This is the highest level seen in five years.1 Find a 95% confidence interval for the proportion of US adults who say they never exercise. Round your answers to three decimal places.
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The population proportion have the following distribution
Solution to the problem
In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by 
and 
. And the critical value would be given by:
The confidence interval for the mean is given by the following formula:
If we replace the values obtained we got:
The 95% confidence interval would be given by (0.175;0.225)
4) fifteen less than y is 32
15 - y= 32
15 - (-17)= 32
two negatives become positive so 15+17= 32
Answer:
f[c(p)] = 0.784p
Step-by-step explanation:
sales discount = 30%
sales tax = 12%
c(p) = 0.7p where p is the original price
f(c) = 1.12c where c is the sales price of the bike.
f[c(p)] = 1.12(0.7p)
f[c(p)] = 0.784p Last option.
Assume: p = 100
c(100) = 0.7(100) = 70
f(70) = 1.12(70) = 78.4
f[70(100)] = 0.784(100) = 78.4
