What is the area under the standard normal curve

Assignment Help Basic Statistics
Reference no: EM131034613

Question 1. A researcher seeking funds for climate change research surveys 371 randomly selected Australians and asks them: "Is global warming a major issue for Australians?" 38 replied that they believed global warming is a major issue. Construct a 95% confidence interval to estimate the proportion of all Australians who feel that global warming is a major issue.

Give the left hand side (the lower limit) of the confidence interval only

Question 2. A company's Human Resources department administers a test of "Executive Aptitude". Test scores are known to be normally distributed with a mean of 100 and a standard deviation of 15.

What score do you need to be in the top 12% of the applicant pool?

What is the score at the 55th percentile?

PayPal is interested in estimating the average number of transactions per year for their active account users.

The number of transactions per year is normally distributed. A random sample of size 25 is obtained from this population. The mean and standard deviation of the number of transactions for this sample are 81 and 9, respectively.

Calculate a 95% confidence interval for the population mean number of transactions. Give the upper limit (the right hand side of the interval) in the space provided.

Question 3. Suppose we now have a sample of size n = 500 from a normal population with

σ (sigma) = 1 and want to calculate a confidence interval for these data.

What is the numerical value of the standard error that we would use?

Question 4. An important step in creating confidence intervals for proportions is to check whether the success/failure conditions have been met otherwise the interval created will not be valid (i.e. we should not have created that interval)!

The following examples are estimating the proportion of the population who likes Brussels sprouts. Try to determine whether or not the assumptions have been met.

In a sample of 150 people surveyed, 36 liked Brussels sprouts.
Answer 1Choose...Conditions not metConditions met
In a sample of 31 people surveyed, 28 liked Brussels sprouts.
Answer 2Choose...Conditions not metConditions met
In a sample of 65 people surveyed, 25 liked Brussels sprouts.
Answer 3Choose...Conditions not metConditions met
In a sample of 104 people surveyed, 100 liked Brussels sprouts.

Question 5. Use Excel to find the Standard Normal Probability for the following questions. Don't forget to sketch the normal distribution and shade the required area.

a) What is the area in the right hand tail of the standard normal curve beyond z = 1.03?

b) What is the area under the standard normal curve between z = -1.20 and z = 0.00?

c) What is the z-value that gives the left hand tail area equal to 0.1010?

d) What is the absolute value of z such that the total area under the standard normal curve between -z and +z will be 0.9610?

Question 6. Suppose we have a sample from a population that has a uniform distribution.

As n (the size of the sample) increases, you would expect the shape of the distribution of sample means to become:

Select one:
a. more normal and more spread out
b. more uniform and more spread out
c. more uniform and less spread out
d. more normal and less spread out

Question 7. Consider a large clothing shop in Sydney. Suppose it is known that the number of business suits sold per day is normally distributed with a mean, μ = 23 and standard deviation, σ = 10. Mr Wood is employed to sell business suits. The number of business suits he sells each day for 40 days is recorded and the mean number per day calculated.

What is the probability that Mr Wood's average daily sales will be more than 29 business suits?

Question 8. Look back at your notes on sampling distributions for means. Consider selecting samples of size 30 from a skewed distribution and assume that 30 is large enough for the Central Limit Theorem to apply.

Indicate which of the following is correct:

Select one:
a. Neither the samples nor the sample means will be normally distributed
b. The sample means could be normally distributed
c. The samples will be normally distributed
d. The samples and their means will be normally distributed

Question 9. The daily exchange rates for the two-year period 2011 to 2013 between the Japanese Yen (JPY) and the Australian Dollar (AUD) can be modelled by a Normal distribution with mean, μ =81 Yen and a standard deviation , σ = 22 Yen.

Draw diagrams and use Excel to help you solve the following problems.

What is the probability that on a randomly selected day during this period, the dollar was worth less than 85 Yen?

What proportion of the days during this period will the dollar be worth between 68 and 85 Yen?

If you select a window of 225 days during this period, how many days would you expect the dollar to worth between 68 and 85 Yen? (round to nearest integer)

Reference no: EM131034613

Questions Cloud

Relationship between job characteristics and job satisfactio : The goal of the research is to find the relationship between job characteristics and job satisfaction. Every bank was surveyed. The small banks were over-represented in the sample. Is the sampling method for answering the research questions a good..
Compare ethical behaviors and societal responsibilities : Compare ethical behaviors and societal responsibilities of companies that operate only in the US and those that operate globally. Explain the concept of cultural difference in business behavior. Explain how globalization is changing business/behavior..
Identify some of recent issues in labelling and packaging : Labelling and packaging has been becoming a very important aspect of marketing. Identify some of the recent issues in labelling, packaging and country of origin in Australia. Students need to go through the current news and media to get the inform..
Would your advice be different if eve has asked adam : Advise Eve of her rights, if any, against Adam and any remedies available for her under common law and Would your advice be different if Eve has asked Adam the exact turnover of the business
What is the area under the standard normal curve : A company's Human Resources department administers a test of "Executive Aptitude". Test scores are known to be normally distributed with a mean of 100 and a standard deviation of 15. What score do you need to be in the top 12% of the applicant pool..
Construct a time series plot for number of vehicles sold : Construct a time series plot for number of vehicles sold. What type of pattern exists in the data? Construct a time series plot for vehicles sales. Comment on the underlying pattern in the time series.
Explains how the global business environment : Develop a 1,400-word report that explains how the global business environment is bringing change to the role of managers in Corporate America. How the economic, sociocultural and legal-political environments influence change.
Integration of e-commerce and erp system : ASSIGNMENT - Integration of E-commerce and ERP system with other ICT (information and communication technologies) to create value for customer and shareholders
Write a paper on us government action on international trade : You are required to prepare a 2,500-3,000-word Research Paper on the topic: U.S. government action on international trade - You must exhibit sound economic analysis as well as strong English and organizational skills in this research work.

Reviews

Write a Review

 

Basic Statistics Questions & Answers

  Statistics-probability assignment

MATH1550H: Assignment:  Question:  A word is selected at random from the following poem of Persian poet and mathematician Omar Khayyam (1048-1131), translated by English poet Edward Fitzgerald (1808-1883). Find the expected value of the length of th..

  What is the least number

MATH1550H: Assignment:  Question:     what is the least number of applicants that should be interviewed so as to have at least 50% chance of finding one such secretary?

  Determine the value of k

MATH1550H: Assignment:  Question:     Experience shows that X, the number of customers entering a post office during any period of time t, is a random variable the probability mass function of which is of the form

  What is the probability

MATH1550H: Assignment:Questions: (Genetics) What is the probability that at most two of the offspring are aa?

  Binomial distributions

MATH1550H: Assignment:  Questions:  Let’s assume the department of Mathematics of Trent University has 11 faculty members. For i = 0; 1; 2; 3; find pi, the probability that i of them were born on Canada Day using the binomial distributions.

  Caselet on mcdonald’s vs. burger king - waiting time

Caselet on McDonald’s vs. Burger King - Waiting time

  Generate descriptive statistics

Generate descriptive statistics. Create a stem-and-leaf plot of the data and box plot of the data.

  Sampling variability and standard error

Problems on Sampling Variability and Standard Error and Confidence Intervals

  Estimate the population mean

Estimate the population mean

  Conduct a marketing experiment

Conduct a marketing experiment in which students are to taste one of two different brands of soft drink

  Find out the probability

Find out the probability

  Linear programming models

LINEAR PROGRAMMING MODELS

Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd