a.) ABC.com posted a question on their website asking viewers to say if they approved ordisapproved of the State of the Union address by the President. 33% said that they approved. Volunteer sample b.) A news reporter stood outside of Tigert (the University of Florida’s administration building) and asked all of those that exited if they thought that tuition should be increased. 100% said that tuition should be increased. Convenience samplec.) A researcher took the University of Florida phone book and chose 60 students to call using a random selection method that a computer program provided. The researcher then called each of these students. 17% of the students said that tuition should be increased. 99.7% % 6895% 5659627468 71 65
Simple random sample 23. Answer the following short questions. a.What is the shape of the normal distribution? Bell/ symmetricb.What does a negative z –score tell you? That the score is below the meanc.What does a positive z-score tell you? That the score is above the meand.What is the symbol for the mean of the Normal distribution? µe.What is the symbol for the standard deviation of the Normal distribution? σf.A political scientist is asking 4000 randomly selected participants if they approve of president’s performance in the past 100 days, yes or no. What is the margin of error? 11= = 0.0158n 4000g.What is the mean and the standard deviation of the Standard Normal Distribution? Mean = 0 and Standard Deviation = 1 h.IQ scores are normally distributed with a mean of 100 and a standard deviation of 16. What is the z-score for someone who has a 90 for an IQ score? 24.The population proportion of Americans that have a gun or revolver in their home is 0.422. You randomly select 55 adults and ask them whether or not they havea gun or revolver in their homes. i)Is this problem about the sample mean or about the sample proportion? sample proportion ii)Check the conditions for the sampling distribution.
n = 55 np ≥15 55(0.422) = 23.21 p = 0.422 n(1-p) ≥15 55(1-0.422) = 31.79 Since both conditions are met we can write the sampling distribution iii)What is the sampling distribution of the statistic? has a Normal distribution with mean equal to 0.422 and .(.))standard error equal to iv)Can we answer probability questions for this problem? __________________yes_______ 25. The population proportion of Americans that are members of a church or synagogue is 0.61. You take a random sample of 50 adults and ask them whether or not they are members of a church or synagogue. i)Is this problem about the sample mean or about the sample proportion? sample proportion ii)Check the conditions for the sampling distribution. n = 50 np ≥15 50(0.61) = 30.5 p= 0.61 n(1-p) ≥15 50(1-0.61) = 19.5 Since both conditions are met we can write the sampling distribution iii)What is the sampling distribution of the statistic?