A random sample of 7 students had the following scores on a quiz: 8 points; 9 points; 8 points; 6 points; 7 points; 6 points; 2 points. Which of the following is the best approximation of the standard deviation of the sample of quiz scores?
1.30 points
2.13 points
2.30 points
3.13 points
A data set consists of 8 values and has a mean of 227.5 gallons. Seven of the data values are as follows: 120 gallons; 280 gallons; 215 gallons; 325 gallons; 200 gallons; 135 gallons; 305 gallons. What is the 8th data value in the set?
220 gallons
230 gallons
240 gallons
250 gallons
Which of the following sets of numbers has a median of 42?
{60, 42, 37, 22, 19}
{16, 28, 42, 48}
{42, 64, 20}
{12, 42, 40, 50}
You are told that the interval that is most likely to contain all the people who walk their dog every day is between 13.5% and 22.1%. What is the margin of error, and what sample size is needed to obtain that margin of error?
±4.3%; 32
±17.8%; 541
±4.3%; 541
±17.8%; 32
In a recent survey of 160 people, 31% said that they spend at least $50 a day on everyday expenses. What is the margin of error for this survey?
about 7.91%
about 0.0079%
about 0.625%
about 14.20%
