Question

**PLEASE ANSWER ALL question**

Suppose you are the manager of Speedy Oil Change which claims that it will change the oil in customers’ cars in less than 30 minutes on average. Further suppose that several complaints have been filed from customers stating that their oil change took longer than 30 minutes. Upper-level management at Speedy Oil Change headquarters has requested that you investigate the complaints. To begin your investigation, you randomly audit 36 oil changes performed by Speedy Oil Change and record the time each customer waited for the oil change. The number of minutes to complete each of the 36 oil changes is reported below. (42 29 19 11 10 27 41 27 22 26 28 32 17 15 25 35 32 22 13 31 17 30 33 25 18 24 28 21 40 19 34 30 14 23 22 10) In the questions below, you will test if the mean wait time is significantly less than 30 minutes at a significance level of 0.01.

1. List the requirements that should be met for this hypothesis test. Have the requirements been met? Justify your answer.

2. Write the null and alternative hypothesis.

3. Calculate the test statistic and the P-value. Label each accordingly. Lab Ch.9-10 continued

4. Would you reject the null hypothesis? Justify your answer using a complete sentence and proper grammar.

5. Is the company fulfilling its promise to “change the oil in customers’ cars in less than 30 minutes on average?” Unfortunately, Speedy Oil Change continues to get customer complaints. As the manager, you feel that perhaps more analysis is needed. You know that you are likely to be asked “how much less than 30 minutes is our mean oil change?”

6. Construct a 98% confidence interval for the mean wait tine. Report this confidence interval accurate to 1 decimal place.

7. State the point estimate and calculate the margin of error.

8. Explain to your superiors how to interpret this interval. Lab Ch.9-10 continued

9. Using the confidence interval you created, calculate the range of values that answers the question “how much less than 30 minutes is our mean oil change?”

10. What other factors might you need to consider in order to address the customer complaints?

Answer #1

5. A car dealer claims that the average wait time for an oil
change is less than 30 minutes. The population of wait times is
normally distributed and 26 customers are sampled. The sample mean
is 28.7 minutes and the standard deviation of the sample is 2.5
minutes. Test the claim at the .05 significance level (α=.05) using
the traditional method.

I need someone to answer this question for me please its
for Statistical Modeling and Data Analysis. Thanks.
1. (65 points)
Waiting at an ER.
A hospital administrator hoping to
improve wait times decides to estimate the average emergency room
waiting time at her hospital. She collects a simple random sample
of 64 patients and determines the time (in minutes) between when
they checked in to the ER until they were first seen by a doctor.
She repeats this 1000...

“Fana Lube” is a regional chain that provides a standard
service for performing oil changes and basic checkups on
automobiles. The chain has a standard that says the average time
per car for this service should be 15 minutes. There is
considerable variability in times due to differences in layout of
engines, degree of time pressure from other jobs, and many other
sources. As a result, the management of the chain decided to study
if the standard is being met...

A very busy and fancy restaurant records the wait time for each
customer that comes in. Below are 12 customers’ wait times (in
minutes):
51
60
59
72
80
83
54
66
61
81
66 62
1.The manager wants to know the percentage of wait times that
are greater than 55 minutes. According to the sample data, what
would be a point estimate of the true percentage of wait times that
are greater than 55 minutes?
2.Use this point estimate...

Recall that a bank manager has developed a new system to reduce
the time customers spend waiting to be served by tellers during
peak business hours. The mean waiting time during peak business
hours under the current system is roughly 9 to 10 minutes. The bank
manager hopes that the new system will have a mean waiting time
that is less than six minutes. The mean of the sample of 104 bank
customer waiting times is x¯x¯ = 5.46. If...

Please answer each question and explain how you found
the correct answer.
2. Additionally, customer satisfaction surveys have indicated
that 65% (p=.65) of all TGP customers rate service as good or
excellent. You are taking a new survey to see if this is still the
case. Assuming a normal distribution, what is the probability
that:
a) your inquiry of 90 customers will provide a sample proportion
within + and - .10 of the population proportion?
b) Your inquiry of 90...

answer all these questions please with the right question number
next to its letter
QUESTION 27
If a you want to investigate the tread life of your company’s
tires, and you took a sample of 10 tires and constructed a 95%
confidence interval, degrees of freedom and t value would be
A
11 degrees of freedom and t value of 2.201
B
10 degrees of freedom and t value of 2.228
C
9 degrees of freedom and t value of...

QUESTION 7
Suppose the observational units in a study are the patients
arriving at an emergency room on a given day, 11 Nov 2019. For the
following indicate whether it can legitimately be considered a
variable or not:
Whether or not men have to wait longer than women
yes
no
5 points
QUESTION 8
A survey company published results of a survey stating that 56%
of the 600 randomly sampled residents planned to set off
firereworks on July...

Based on your recommendations, Mr. Miller improved shop
operations and successfully reduced the number of customer
complaints. To maintain good service, Mr. Miller asked you to keep
monitoring the wait times of oil change customers
at the shop.
First, you decide to create an x-bar chart to
monitor the central tendency (i.e., mean). But you know that we
sometimes overlook a problem if we use only an x-bar chart.
Therefore, you decide to create an R-chart to
monitor the process...

Check the requirements for confidence intervals using the following
information:
suppose we want to estimate the mean number of concerts that
rock bands schedule every year. A random sample of 75 rock bands
finds a mean sample of 38 scheduled concerts every year. with this
information, you plan to create a 95% confidence interval for the
true mean number of concerts rock bands schedule every year
conditions
1. the method of sampling :
a. can be safely assumed to be...

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