Question

1. I wanted to estimate the population mean number of cups of coffee people drink in a day. I asked a group of 10 friends how many cups of coffee they have in a day. I received the following results: 2, 2, 3, 2, 0, 5, 1, 4, 2, 1. For my population mean, I am choosing a 95% confidence level.

2. I decided to go with option two and go with the car theme because I just bought a Hyundai Elantra. I found that Hyundai sold 175,094 Elantra's in 2019. Across all its models, Hyundai sold 688,771 cars in 2019. I decided to calculate a 90% confidence interval for the population proportion.

3. I would like to study is family members that have been on a sports team within the last year. My numbers I obtained from 10 different families are as followed 1, 3, 0, 2, 1, 4, 0, 2, 2 and 3. I will choose 95% confidence interval for my population mean.

For your response to a classmate (two responses are required, one in each option), solve a classmate’s confidence interval problem using a confidence level not previously used for that specific classmate’s problem. Make sure that you use appropriate terminology to state the problem and explain your solution.

Answer #1

Que.1

95% confidence interval for population mean:

Here

We are 95% confident that mean number of cups of coffee people drink in a day is lie between 1.14 to 3.26

Que.2

90% confidence interval for the population proportion:

Here

We are 90% confident that proportion of Elantra sold by Hyundai in 2019 lies between 0.249 to 0.251.

Que.3

95% confidence interval for population mean:

Here

I have taken a (random) sample of the gas mileage gotten by my
Hyundai Elantra for 20 tanks.
The results are given below: 22.4 26.8 29.5 34.4 22.7 30 28.2
26.5 25 25.6 27.2 24.2 26.8 28.1 25.6 24.6 28.5 26.3 24.1 29.7
a) (4 pts) Find the mean and sample standard deviation.
b) (6 pts) Assuming the population is roughly normal, find a 90%
confidence interval for the mean gas mileage of my Hyundai
Elantra.
c) (6 pts) Assuming...

I believe that the population mean number of times a person
bought hot coffee in a week is less than 4 per week. I spoke with
12 people and they said the number of coffees they bought per week
are as follows 5, 3, 5, 2, 1, 0, 5, 4, 4, 2, 3, and 5. Assume a 95%
confidence interval and assume a random sample.

My sisiter-in-law manages a tim hortons coffee shop. According
to her, the number of cups of coffee sold every day is normally
distributed with mean μ=7000 and standard deviation σ = 750.
1) Find a constant b such that there is a 5% chance that the
total number of cups sold in a 5-day period will exceed b.
2) The probability is 0.47725 that the mean daily number of cups
of coffee sold over an n-day period is between 6700...

Confidence interval for the population mean using random
sampling.
I work with 6 other people in an office, all of which are in
different stages of life, some with family, some not. Some older,
some younger, kids/no kids, and so on.
I asked them how many times weekly that they go to the grocery
store.
Person 1 - 5 times
Person 2 - 1 time
Person 3 - 0 times
Person 4 - 2 Times
Person 5 - 1 Time...

I wanted to estimate the average height in feet of pine trees in
my neighborhood. A random selection of 15 trees is as follows in
feet: 48, 52, 92, 69, 75, 61, 85, 58, 79, 63, 73, 62, 57, 81, 68.
What are the results of a 95% confidence interval for the mean
height of pine trees in my neighborhood? Example: The following 95%
Confidence Interval for a population mean is given, (3.6, 4.4).
Find Lower Limit Find upper Limit...

Estimate the population mean number of times that women go to
Sephora each month. I spoke with 8 people and I know and found that
they went out 3,2,3,4,1,2,1 and 3 times last month. Calculate a 75%
confidence interval for the population mean.
Sample Mean_____
Standard Error_____
Standard Deviation_____
Lower Limit _____
Upper Limit ______

Think about a population mean that you may be interested in and
propose a hypothesis test problem for this parameter. Gather
appropriate data and post your problem and solution in the
discussion topic.
For example, you may believe that the population mean number of
times that adults go out for dinner each week is less than 1.5.
Your data could be that you spoke with 7 people and found that they
went out 2, 0, 1, 5, 0, 2, and...

The HR Department wants to estimate the interval for the
population mean number of absences in a quarter for the agency’s
employees using the following data at the 95 percent level of
confidence. Number of absences (in days) for a random sample of 10
employees 0 1 1 2 2 2 3 4 6 9

7. If I have a population of an unknown mean and unknown
standard deviation, what is the 95% confidence interval estimate of
the mean if a. A random sample of size 25 gives a mean of 50 and a
standard deviation of 12 b. A random sample of size 16 gives a mean
of 50 and a standard deviation of 12
8. The average cost per night of a hotel room in New York City
is $325. Assume this estimate...

1. I want to estimate the average amount of people who drink
coffee in the morning. How many people should I poll to be 97%
confident that I am within 1.5% of the actual proportion?
Part 2
Repeat , but assume the last year the polls showed that 40%
drink coffee.
Part 3
I want to estimate the average amount of money that customers at
Starbucks spend on purchase. How many people should I poll to be
99% confident that...

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