. Parking at a large university has become a very big problem. University admini
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Question
. Parking at a large university has become a very big problem. University administrators are interested in determining the average parking time (e.g. the time it takes a student to find a parking spot) of its students. An administrator inconspicuously followed 140 students and carefully recorded their parking times. The parking times recorded followed a distribution that was skewed to the right. Based on this information, discuss the relationship between the mean and the median for the 140 student parking times collected.
5. At a tennis tournament a statistician keeps track of every serve. The statistician reported that the mean serve speed of a particular player was 104 miles per hour (mph) and the standard deviation of the serve speeds was 8 mph. Assume that the statistician also gave us the information that the distribution of the serve speeds was bell shaped. What proportion of the players serves are expected to be between 112 mph and 120 mph?
6. The amount of television viewed by todays youth is of primary concern to Parents Against Watching Television (PAWT). 300 parents of elementary school-aged children were asked to estimate the number of hours per week that their child watched television. The mean and the standard deviation for their responses were 16 and 4, respectively. PAWT constructed a stem-and-leaf display for the data that showed that the distribution of times was a bell-shaped distribution. Give an interval around the mean where you believe most (approximately 95%) of the television viewing times fell in the distribution.
7. At a tennis tournament a statistician keeps track of every serve. The statistician reported that the mean serve speed of a particular player was 98 miles per hour (mph) and the standard deviation of the serve speeds was 14 mph. If nothing is known about the shape of the distribution, give an interval that will contain the speeds of at least eight-ninths of the players serves.
8. A study was designed to investigate the effects of two variables - (1) a students level of mathematical anxiety and (2) teaching method - on a students achievement in a mathematics course. Students who had a low level of mathematical anxiety were taught using the traditional expository method. These students obtained a mean score of 480 with a standard deviation of 20 on a standardized test. Assuming no information concerning the shape of the distribution is known, what percentage of the students scored between 440 and 520?
Explanation / Answer
5)
mean = 104, std. deviation = 8
by normal distribution,
P(112 < X < 120)
= P[ ( 112 -104) / 8 < z < ( 120 - 104)/8]
= P(1 < Z < 2)
= .1359
8)
mean = 480 , std. deviation = 20
by normal distribution,
P(440 < X < 520)
= P[ ( 440 - 480) / 20 < z < ( 520 - 480)/20]
= P(-2 < Z < 2)
= .9545
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