Stat 160 Prequiz over Section 2.1 through 2.4



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1. Suppose the sample space consists of heights of humans. Which of the following is not an event?

A. Over six feet tall.
B. Under five foot two.
C. Eyes of blue.
D. Taller than the average height.
2. I want to test the fairness of flipping the next quarter to be used in the Super Bowl. I flip this quarter 50 times and count the number of heads. I then flip another quarter 50 times and also count the number of heads. I then take the total number of heads divided by 100 to find the probability of getting heads. Did this experiment violate the identical trials rule?

A. No, a quarter is a quarter
B. Yes, changing quarters violates the identical trial rule. We didn't use the same quarter throughout the experiment.
C. It depends on whether or not the 2 quarters were minted the same year. Quarters from the same year are identical.
D. No, if the quarters weigh the same we can assume they are identical.
3. I flip a coin twice. I want to know the probability of getting two heads. Which of the following is the sample space (H represents heads and T represents tails)?

A. {HT, HH, TH, TT}
B. {HH}
C. {0}
D. {HT, TH, TT}
4. Suppose we roll two fair dice. What's the probability that the sum of the upfaces is 10? Here's the plot of the sample space from the section More on Probability. First determine how many points which have coordinates that add to 10.

 
 
        6 -     *         *         *         *         *         *
  Die 2   -
          -
        5 -     *         *         *         *         *         *
          +
          -
          -
        4 -     *         *         *         *         *         *
          -
          +
        3 -     *         *         *         *         *         *
          -
          -
        2 -     *         *         *         *         *         *
          +
          -
        1 -     *         *         *         *         *         *
            ----+---------+---------+---------+---------+---------+--Die 1 
                1         2         3         4         5         6


A. 8/36.
B. 3/36.
C. 0.
D. 1.