A study by Allstate Insurance Co. finds that 82% of teenagers have used cell phones while driving (The Wall Street Journal, May 5, 2010). In October 2010, Massachusetts enacted a law that forbids cell phone use by drivers under the age of 18. A policy analyst would like to determine whether the law has decreased the proportion of drivers under the age of 18 who use a cell phone.
which one is correct H0 and H1 statement?
a. 
H0: proportion of teenagers who used cell phones while driving = 0.82 H1: proportion of teenagers who used cell phones while driving ≠ 0.82 

b. 
H0: proportion of teenagers who used cell phones while driving < 0.82 H1: proportion of teenagers who used cell phones while driving = 0.82 

c. 
H0: proportion of teenagers who used cell phones while driving = 0.82 H1: proportion of teenagers who used cell phones while driving < 0.82 

d. 
H0: proportion of teenagers who used cell phones while driving = 0.82 H1: proportion of teenagers who used cell phones while driving > 0.82 
Which one is correct statement? Choose all applied.
a. 
How to choose a level of alpha should be based on sampling error. 

b. 
Person who select the value of alpha is a person who does the test. 

c. 
Definition of pvalue is that when the null statement is true, it is probability that test statistics would take a value as actually observed or more extreme than actually observed 

d. 
Critical value approach and pvalue approach do not give us same conclusion all the time. 
Here we want to test whether the proportion of teenagers who used cell phone while driving has decreased from 0.82 after the law .
Let p be the proportion .
Then our Hypotheses will be
Ho : p = 0.82 vs H1 : p< 0.82
C.H0 : Proportion of teenagers who used cell phones while driving = 0.82
H1 : proportion of teenagers who used cell phones while driving < 0.82
In Hypothesis testing the researcher who is performing the test determines that what will be the level of significance . That means what percentage of type 1 error will he allow.
So statement (b) is correct .
And the p Value means probability of obtaining a test statictic as observed or more extreme than the observed value when the Null hypothesis is true .
So statement (c) is correct .
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