1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
n200080 [17]
1 year ago
10

The bank manager wants to show that the new system reduces typical customer waiting times to less than 6 minutes. One way to do

this is to demonstrate that the mean of the population of all customer waiting times is less than 6. Letting this mean be µ, in this exercise we wish to investigate whether the sample of 107 waiting times provides evidence to support the claim that µ is less than 6.
For the sake of argument, we will begin by assuming that µ equals 6, and we will then attempt to use the sample to contradict this assumption in favor of the conclusion that µ is less than 6. Recall that the mean of the sample of 107 waiting times is = 5.27 and assume that σ, the standard deviation of the population of all customer waiting times, is known to be 2.23.



(a) Consider the population of all possible sample means obtained from random samples of 107 waiting times. What is the shape of this population of sample means? That is, what is the shape of the sampling distribution of ?







(b) Find the mean and standard deviation of the population of all possible sample means when we assume that µ equals 6. (Round your answer to 4 decimal places.)







(c) The sample mean that we have actually observed is = 5.27. Assuming that µ equals 6, find the probability of observing a sample mean that is less than or equal to = 5.27. (Round "z-value" to 2 decimals and final answer to 4 decimal places.)







(d) If µ equals 6, what percentage of all possible sample means are less than or equal to 5.27? What do you conclude about whether the new system has reduced the typical customer waiting time to less than 6 minutes? (Round your answer to 2 decimal places.)
Mathematics
1 answer:
Kruka [31]1 year ago
8 0

The shape of the population sample means is large, the mean and standard deviation is 6 and 0.2155, the probability of sample mean is 0.37172 and it is conclude that mean is less than 6.

Given that sample of 107 waiting times provides evidence to support the claim that µ is less than 6 and for the waiting times mean is \bar{x}=5.27 and standard deviation is 2.23.

(a) It is observed that the sample size n=107, population mean μ=6, sample mean \bar{x}=5.27, and population standard deviation σ=2.23.

The Central Limit Theorem (CLT) states that for a large number of samples, the sample mean tends to approximate the standard value. Using this, it can be asserted that the sample mean follows an approximate normal distribution with μ and variance σ²/n. So, this data will follows a normal distribution because it is very large.

(b) The given mean of all samples is μ=6.

The standard error (SE) is same as the standard deviation of the sample mean. SE is computed as shown below:

SE=√(σ²/n)

SE=σ/√n

SE=2.23/√107

SE=0.2155

In notations,

\bar{x}\sim N(\mu=6,SE=0.2155)

(c) For a single mean (n=1), the z-score is given as follows:

\begin{aligned}z&=\frac{\bar{x}-\mu}{\sigma}\sim N(0,1)\\ &=\frac{\bar{x}-6}{2.23}\end{aligned}

Then, the probability less than or equal to 5.27 is computed as given below:

\begin{aligned}P(\bar{x}\leq 5.27)&=P\left(\frac{\bar{x}-6}{2.23}\leq \frac{5.27-6}{2.23}\right)\\ &=P(z\leq -0.3273)\\ &=P(z > 0.3273)\\ &=1-P(z \leq 0.3273)\end{aligned}

Using the normal table, it is found out that  P(z≤0.3273)=0.6282

\begin{aligned}P(\bar{x}\leq 5.27)&=1-0.62828\\&=0.37172\end

d. If the population mean =6 and sample mean is 5.27 then there is 3.71% that sample mean is less than 5.27 hence we conclude that means is less than 6.

Hence, when  the mean of the sample of 107 waiting times is = 5.27 and assume that σ, the standard deviation is known to be 2.23. the shape of the population sample means is large, the mean and standard deviation is 6 and 0.2155, the probability of sample mean is 0.37172 and it is conclude that mean is less than 6.

Learn more about the standard deviation from here brainly.com/question/16903717

#SPJ9

You might be interested in
Simplify the following expression -12(5x-4)
faltersainse [42]
The answer would be 60x-48
3 0
3 years ago
Read 2 more answers
Karl is building a rectangular garden bed. The length is 6 feet. She has 20 feet of boards to make the sides. Write and solve an
natali 33 [55]

Answer:

The width of the garden bed must be less than or equal to 4 feet.

w\leq4

Explanation:

Given that;

She has 20 feet of boards to make the sides.

The perimeter of the garden bed must not be more than 20 feet

\begin{gathered} P=2l+2w\leq20 \\ 2l+2w\leq20 \end{gathered}

Given;

The length is 6 feet;

l=6

To get the inequality for the width w, let us substitute the value of the length into the inequality above and simplify;

\begin{gathered} 2l+2w\leq20 \\ 2(6)+2w\leq20 \\ 12+2w\leq20 \\ 2w\leq20-12 \\ 2w\leq8 \\ \frac{2w}{2}\leq\frac{8}{2} \\ w\leq4 \end{gathered}

Therefore, the width of the garden bed must be less than or equal to 4 feet.

w\leq4

8 0
1 year ago
Solve the equation <br><br>9y^3+8y=4y+18y^2
kari74 [83]
9y^3+8y=4y+18y^2
9y^3-18y^2+4y=0

*Divide the whole thing by y

9y^2-18y+4=0

*use quadratic formula to solve
3 0
3 years ago
A tree is broken at a height of 5 m from the ground and its top touches the ground at a distance of 12 m from the base of the tr
frozen [14]

Answer:

The original height of the tree is 18 m.

Step-by-step explanation:

Please see attached photo for explanation.

From the diagram, we shall determine the value of 'x'. This can be obtained by using the pythagoras theory as follow:

x² = 5² + 12²

x² = 25 + 144

x² = 169

Take the square root of both side

x = √169

x = 13 m

Finally, we shall determine the original height of the tree. This can be obtained as follow.

From the question given above, the tree was broken from a height of 5 m from the ground which form a right angle triangle with x being the Hypothenus as illustrated in the diagram.

Thus, the original height of the will be the sum of 5 and x i.e

Height = 5 + x

x = 13 m

Height = 5 + 13

Height = 18 m

Therefore, the original height of the tree is 18 m.

3 0
2 years ago
Students from two age groups were surveyed to see how they travel to school. Here are the results:
liq [111]

Answer:

The table representing the number of students by which mode of transport they travel is given as:

                              Walk or bike    Bus       Car     Row Total

Below age 15            87                    60        18           165

Age 15 and above   65                    50        80         195

Column Total            152                  110        98         360

We know that a relative frequency of an event is the ratio of frequency to the total number of trials.

i..e we divide each frequencies by 360 to obtain a two-way relative frequency.

Hence,the table is given as:

                              Walk or bike    Bus       Car     Row Total

Below age 15            0.24               0.17      0.05         0.46

Age 15 and above    0.18                0.14      0.22        0.54

Column Total             0.42               0.31     0.27          1                        

6 0
3 years ago
Read 2 more answers
Other questions:
  • How many possible bends could this graph have?
    9·2 answers
  • An average person in the United States throws away 4.5 × 10² g of trash per day. In 2013, there were about 3.2×106 people in the
    5·1 answer
  • In the diagram below what is the relationship between the number of rectangles in the perimeter of the figure they form?
    13·1 answer
  • 1. An LG Dishwasher, which costs $800, has a 20% chance of needing to be replaced in the first 2 years of purchase. A two-year e
    15·1 answer
  • The teacher buys 24 small boxes, 12 medium boxes, and 5 large boxes. She had to return 3 small boxes due to defects. How many co
    13·1 answer
  • How would you find the value of x
    14·1 answer
  • There were 239 people at a Travis Scott concert. Admission to the drive-in concert was $15 for adults and $5.50 for children. Th
    7·1 answer
  • Use the GCF and the distributive property to find the expression that is
    11·1 answer
  • Ive been stuck for so long. pls help
    7·1 answer
  • A bag of fruit contains 3 apples, 2 oranges, 1 banana, and 4 pears, Gerald will randomly select two pieces of fruit
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!