Ur answer is B- 4/5 because when u subtract them u get 0.8 and then u have to turn it as a fraction then it will be 8/10 then u simplify it and u get 4/5.

Hope u get it right!

7 0

3 years ago

Read 2 more answers

Suppose that the speeds of cars travelling on California freeways are normally distributed with a mean of 61 miles/hour. The hig

cricket20 [7]

Answer:

The standard deviation of the speeds of cars travelling on California freeway is 6.0088 miles per hour.

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by

$Z = \frac{X - \mu}{\sigma}$

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 pvalue, we This p-value is the probability that the value of the measure is greater than X.

In this problem, we have that:

Suppose that the speeds of cars travelling on California freeways are normally distributed with a mean of 61 miles/hour. This means that $\mu = 61$ .

The highway patrol's policy is to issue tickets for cars with speeds exceeding 75 miles/hour. The records show that exactly 1% of the speeds exceed this limit. This means that the pvalue of Z when $X = 75$ is 0.99. This is $Z = 2.33$

$Z = \frac{X - \mu}{\sigma}$

$2.33 = \frac{75 - 61}{\sigma}$

$2.33\sigma = 14$

$\sigma = \frac{14}{2.33}$

$\sigma = 6.0088$

The standard deviation of the speeds of cars travelling on California freeway is 6.0088 miles per hour.

6 0

3 years ago