An SRS of 1000 students are asked, "Do you think cell phones make people happier?" If in fact 30% of the population of students believe that cell phones do indeed increase happiness, then what are the chances that at most 31% of the people in the sample will answer "yes"?
for normal distribution z score =(p̂-p)/σp | |
here population proportion= p= | 0.300 |
sample size =n= | 1000 |
std error of proportion=σp=√(p*(1-p)/n)= | 0.0145 |
chances that at most 31% of the people in the sample will answer "yes":
probability =P(X<0.31)=(Z<(0.31-0.3)/0.014)=P(Z<0.69)=0.7549 |
An SRS of 1000 students are asked, "Do you think cell phones make people happier?" If...
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