We know that :
So, let the diameter of this circle be x.
Which means :
Thus, the radius of the circle Robert drew = 6 m
Since the circle in option B has a radius of 6 m, it is the circle Robert drew.
▪︎<em>Therefore, the correct option is (B)</em>
Answer:
When we compare the significance level we see that
so we can reject the null hypothesis at 10% of significance. So the the true mean is difference from 21 at this significance level.
Step-by-step explanation:
Data given and notation
represent the sample mean
represent the population standard deviation
sample size
represent the value that we want to test
represent the significance level for the hypothesis test.
z would represent the statistic (variable of interest)
represent the p value for the test (variable of interest)
State the null and alternative hypotheses.
We need to conduct a hypothesis in order to check if the average age of the evening students is significantly different from 21, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
The statistic is given by:
(1)
Calculate the statistic
We can replace in formula (1) the info given like this:
P-value
Since is a two sided test the p value would be:
Conclusion
When we compare the significance level we see that
so we can reject the null hypothesis at 10% of significance. So the the true mean is difference from 21 at this significance level.
Answer:
The child's reading level is at the 3.4th percentile.
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean and standard deviation
, the z-score of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
You do some research and determine that the reading rates for their grade level are normally distributed with a mean of 90 words per minute and a standard deviation of 24 words per minute.
This means that
You find an individual that reads 46.4 word per minute. At what percentile is the child's reading level?
The percentile is the p-value of Z when X = 46.4, multiplied by 100. So
has a p-value of 0.034.
0.034*100 = 3.4
The child's reading level is at the 3.4th percentile.