Statistical Sciences 2244A/B Lecture Notes - Lecture 7: Interval Estimation, Statistical Parameter, Statistic

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scarletgnu752

13 Apr 2018

School

Western University

Department

Statistical Sciences

Course

Statistical Sciences 2244A/B

Professor

Jennifer Waugh

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Document Summary

For quantitative data use mu for the mean of a population. The mean of the sample is x bar; average of observations in the sample. X bar from a sample or an experiment is an estimate of the mean mu of the underlying population. For qualitative data use p to indicate the population proportion; a parameter often of unknown value. The sample proportion p hat, is the proportion of individuals of a given type in a sample or an experiment; an estimate of the population proportion p. 95% con dence interval for mu: interval of numbers between the values x bar - 1. 4 and x bar. Most con dence intervals take the form (estimate +- margin of error) The estimate is the centre of the interval; our unbiased guess for the value of the unknown parameter, based on sample data.

Related Questions

1. Matt, the manager, wants to estimate the mean wait time for customers to check out in his Mini-Market. He randomly selects customers and determines the mean wait time is minutes. Define the following for this exercise:

a) Is the data collected qualitative or quantitative?

b) Variable (x):

c) Population of Interest:

d) Sample:

e) Parameter of Interest and Statistic: Do you expect the parameter and the statistic to be the same value? Explain.

f) Discuss the use of descriptive and inferential statistics in this exercise.

g) Is the variable, x, discrete or continuous?

2. Identify the population and sample for the following examples:

The P.E. coach of a middle school interested in the mean height for the graders in the school. He randomly selects graders and measures the height of each.

a) Population:

b) 7thgraders Sample:

c) A community college notices that an increasing number of full-time students are working while attending school. The administration randomly selects 200 students and determines how many hours per week each student works.

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1. Matt the Manager wants to estimate the mean wait time for customers to check out in his Mini-Market. He randomly selects 40 customers and determines the mean wait time is 2.7 minutes. Define the following for this exercise:Experimental Unit or Individual: Is the data collected qualitative or quantitative?Variable (x):Population of Interest:Sample:Parameter of Interest:Statistic:Do you expect the parameter and the statistic to be the same value? Explain.Discuss the use of descriptive and inferential statistics in this exercise.Is the variable, x, discrete or continuous?

2. Identify the populationand samplefor the following examples:a)The P.E. Coach of a middle school interested in the mean height for the 7thgraders in the school. He randomly selects 40 7thgraders and measures the height of each.Population: 7thgraders Sample: 40 7thgraders chosenb)A community college notices that an increasing number of full-time students are working while attending school. The administration randomly selects 200 students and determines how may hours per week each students works.

fuchsiatermite35

Statistical Sciences 2244A/B Lecture Notes - Lecture 7: Interval Estimation, Statistical Parameter, Statistic

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