Maintaining your balance may get harder as you grow older. A study was conducted to see how steady the elderly are on their feet. They had a random sample of subjects stand on a force platform and have them react to a noise. The force platform then measured how much they swayed forward and backward, and the data are in the table below. Do the data show that the mean elderly sway measurement is higher than the mean forward sway of younger people, which is 18.125 mm? Test at the 7% level.

forward sway in mm 18 31 1 12 17 10 19 29 17 16 27 25 27 33 3 17 14 30 22 29 14 33 26 19 20 31 31 17 8 23 9 27 34 11 36 31 30 10 10 33

P: Parameter

     What is the correct parameter symbol for this problem?

      ?   N   X   s   μ   p̂   n   σ   p   X̄  

     What is the wording of the parameter in the context of this problem?

      Select an answer   40 randomly selected elderly people   All elderly people   A randomly selected elderly person   The mean forward sway of all elderly people   The forward sway of a randomly selected elderly person   The mean forward sway in 40 randomly selected elderly people  

H: Hypotheses

     Fill in the correct null and alternative hypotheses:

H0:H0:  ?   X̄   n   σ   μ   p   X   p̂   N   s    ?   ≥   <   =   ≤   ≠   >   18.125 mm 

HA:HA:  ?   p   n   p̂   μ   N   X̄   X   σ   s    ?   <   >   =   ≥   ≤   ≠   18.125 mm 

A:  Assumptions

     Since  Select an answer   qualitative   quantitative   information was collected from each object, what conditions do we need to check?

     Check all that apply.

    

1. 1. no outliers in the data
   2. n(pˆ)≥10n(p̂)≥10

     Check those assumptions:

     1. Is the value of σσ known?  ?   yes   no  

 

 

 

 

Americans Using Facebook and LinkedIn. A 2018 Pew Research Center survey (Pew Research website) examined the use of social media platforms in the United States. The survey found that there is a 68 probability that a randomly selected American will use Facebook and a. 25 probability that a randomly selected American will use LinkedIn. In addition, there is a. 22 probability that a randomly selected American will use both Facebook and LinkedIn. 

(a) What is the probability that a randomly selected American will use Facebook or LinkedIn?

(b) What is the probability that a randomly selected American will not use either social media platform.

The probability that a randomly selected person has high blood pressure (the event H) is p(H)=0.2 and the probability that a randomly selected is a runner (the event R) is P(R)=0.4. The probability that a randomly selected person has blood pressure and is a runner is 0.1. Find the probability that a randomly selected person is a runner, given that he has high blood pressure.

(a) 0

(b) 0.25

(c) 1

(d) 0.50

(e) 0.17

(f) None of the above

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.