MZAOB = 6x- 12°<br> mZBOC = 3x+ 30°<br> Find mZAOB:

Exhibit 9-2 The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the cu

Diano4ka-milaya [45]

Answer:

At a .05 level of significance, it can be concluded that the mean of the population is significantly more than 3 minutes.

Step-by-step explanation:

We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes.

At the null hypothesis, we test if the mean is of at most 3 minutes, that is:

$H_0: \mu \leq 3$

At the alternative hypothesis, we test if the mean is of more than 3 minutes, that is:

$H_1: \mu > 3$

The test statistic is:

$z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$

In which X is the sample mean, $\mu$ is the value tested at the null hypothesis, $\sigma$ is the standard deviation and n is the size of the sample.

3 is tested at the null hypothesis:

This means that $\mu = 3$

The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes. The population standard deviation is known to be 0.5 minute.

This means that $n = 100, X = 3.1, \sigma = 0.5$

Value of the test statistic:

$z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$

$z = \frac{3.1 - 3}{\frac{0.5}{\sqrt{100}}}$

$z = 2$

P-value of the test and decision:

The p-value of the test is the probability of finding a sample mean above 3.1, which is 1 subtracted by the p-value of z = 2.

Looking at the z-table, z = 2 has a p-value of 0.9772.

1 - 0.9772 = 0.0228

The p-value of the test is of 0.0228 < 0.05, meaning that the is significant evidence to conclude that the mean of the population is significantly more than 3 minutes.

6 0

3 years ago

Victoria and margaret left their apartment at the same time traveling in the same direction. victoria drove at 55 mph and margar

Lady bird [3.3K]

I believe you would multiply it by 2 and add on the multiples after you .

8 0

3 years ago

What is the slope of this graph

telo118 [61]

Answer: positive I think

Step-by-step explanation:

4 0

2 years ago

Solve by using substitution 2x-5=-y x+3y=0

kirill115 [55]

Answer:

(3,-1)

Step-by-step explanation:

1) Solve equation for y

2) Plug into other equation

3) Solve for x

4) Plug in the value found for x

5) Solve for y

5 0

3 years ago

The mean annual salary for intermediate level executives is about $74000 per year with a standard deviation of $2500. A random s

lidiya [134]

Answer:

11.51% probability that the mean annual salary of the sample is between $71000 and $73500

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

Problems of normally distributed samples are 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:

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

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 pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .