Quiz 4: Probability

One of the primary feeds for beef cattle is corn. The following table presents the average price in dollars for a bushel of corn and a pound of ribeye steak for 10 consecutive months. Corn Price (\ / bu ) Ribeye Price (\ / lb) 5.82 13.01 5.70 12.24 5.80 13.01 5.84 12.94 6.56 13.89 6.21 13.04 6.39 13.01 6.61 13.76 6.06 12.53 5.84 12.95 The correlation coefficient between the corn price and the ribeye price is 0.773. Which of the following is the best interpretation of the correlation coefficient?

The following display from a graphing calculator presents the least-squares regression line for predicting the price of a certain commodity (y) from the price of a barrel of oil(x). Predict the commodity price when oil costs $107 per barrel.

Characterize the relationship shown in the figure.

One of the primary feeds for beef cattle is corn. The following table presents the average price in dollars for a bushel of corn and a pound of ribeye steak for 10 consecutive months. Corn Price (\ / bu ) Ribeye Price (\ / lb) 5.89 12.94 6.66 14.20 6.07 13.05 5.72 12.86 6.20 13.61 6.42 13.24 5.81 12.98 6.68 13.45 5.75 12.13 5.90 12.79 Construct a scatter plot of the price of ribeye (y) versus the price of corn (x)

Compute the correlation coefficient. x 3 4 5 6 7 8 y 86 77 113 119 133 128

The following table presents the number of police officers (per 100,000 citizens) and the annual murder rate (per 100,000 citizens) for a sample of cities. Police Officers (per 100,000) Murders (per 100,000 per yr) 1377 32 1324 38 1068 47 1443 33 1289 42 1206 39 Compute the correlation coefficient between the per capita number of police officers and the per capita murder rate.

Compute the least-squares regression line for predicting y from x given the following summary statistics: =6.7 =1.6 =23.8 =6.5 r=0.93

One of the primary feeds for beef cattle is corn. The following table presents the average price in dollars for a bushel of corn and a pound of ribeye steak for 10 consecutive months. Corn Price (\ /) Ribeye Price (\ /) 6.34 13.22 5.93 12.06 6.45 13.72 6.19 12.75 6.56 13.27 5.94 12.17 The least-squares regression line for predicting the ribeye price from the corn price is $y = - 1.7478 + 2.3437 x$ . If the price of corn differs by $\$ 0.35$ per bushel, by how much would you expect the price , ribeye to differ?

For which of the following scatter plots is the correlation coefficient an appropriate summary?

One of the primary feeds for beef cattle is corn. The following table presents the average price in dollars for a bushel of corn and a pound of ribeye steak for 10 consecutive months. Corn Price (\ /) Ribeye Price (/) 5.76 12.56 6.45 13.97 5.70 12.07 6.17 12.52 6.61 13.51 5.89 11.97 Compute the least-squares regression line for predicting the ribeye price from the corn pri

The common cricket can be used as a crude thermometer. The colder the temperature, the slower the rate of chirping. The table below shows the average chirp rate of a cricket at various temperatures. Chirp Rate (chirps/second) Temperature 2.4 61.9 3.8 83.6 3.7 71.8 2.0 47 3.4 65.1 3.9 75.8 Compute the least-squares regression line for predicting the temperature from the chirp ra

One of the primary feeds for beef cattle is corn. The following table presents the average price in dollars for a bushel of corn and a pound of ribeye steak for 10 consecutive months. Corn Price (\ /) Ribeye Price (\ /) 6.35 12.87 6.20 13.30 5.82 11.85 6.18 12.64 6.00 12.29 6.57 14.16 The least-squares regression line for predicting the ribeye price from the corn price is $y = - 4.8904 + 2.8678 x$ . Predict the ribeye price in a month when the corn price was $\$ 6.40$ per bushel.

The following table presents the number of police officers (per 100,000 citizens) and the annual murder rate (per 100,000 citizens) for a sample of cities. Police Officers (per 100,000) Murders (per 100,000 per yr) 1196 38 1351 36 1250 40 1500 27 1319 33 1483 35 Construct a scatter plot of the per capita murder rate (y)versus the per capita number of police officers (x).

The following table presents the number of police officers (per 100,000 citizens) and the annual murder rate (per 100,000 citizens) for a sample of cities. Police Officers (per 100,000) Murders (per 100,000 per yr) 1109 46 1238 44 1235 38 1298 40 1077 49 1076 42 The correlation coefficient between the per capita number of police officers and the per capita murder rates -0.666. Which of the following is the best interpretation of the correlation coefficient?

The following display from a graphing calculator presents the least-squares regression line for predicting the price of a certain commodity (y) from the price of a barrel of oil (x) Write the equation of the least-squares regression line.

Compute the least-squares regression line for the given data set. x 2 3 4 5 6 7 y 17.1 18.6 22.7 23.4 25.3 29

The following display from a graphing calculator presents the least-squares regression line for predicting the price of a certain commodity (y) from the price of a barrel of oil (x). What is the correlation between the oil price and the commodity price?

The common cricket can be used as a crude thermometer. The colder the temperature, the slower the rate of chirping. The table below shows the average chirp rate of a cricket at various temperatures Chirp Rate (chirps/second) Temperature 3.4 74 3.1 61.3 1.9 45.7 1.0 35.4 1.4 49 2.5 66 The least-squares regression line for predicting the temperature from the chirp rate is $y = 24.3278 + 13.9423 x$ . If two chirp rates differ by $1.5$ chirps per second, by how much would the temperature differ?

The common cricket can be used as a crude thermometer. The colder the temperature, the slower the rate of chirping. The table below shows the average chirp rate of a cricket at various temperatures Chirp Rate (chirps/second) Temperature 2.9 61.4 2.0 55.5 3.8 77.5 2.5 58.8 1.7 53.4 1.6 52.6 The least-squares regression line for predicting the temperature from the chirp rate is $y = 34.0812 + 10.6698 x$ . Predict the temperature if the chirp rate is $3.6$ chirps per second.

One of the primary feeds for beef cattle is corn. The following table presents the average price in dollars for a bushel of corn and a pound of ribeye steak for 10 consecutive months Corn Price (\ /bu) Ribeye Price (\ / b) 6.40 13.20 6.08 13.21 6.11 13.30 6.37 13.55 5.91 12.57 6.22 13.37 6.49 13.54 6.20 13.37 6.00 12.88 6.04 12.71 Compute the correlation coefficient between the corn price and the ribeye price.