Exam 2: Describing Data: Numerical

Consider the following sample data: 153,178,203,410,310,231,190,and 225.Compute the mean and median.Is the distribution of these numbers skewed to the right,skewed to the left or symmetric? Why?

A company produces flashlight batteries with a mean lifetime of 5,200 hours and a standard deviation of 100 hours. a.Find the z-score for a battery which lasts only 5,100 hours b.Find the z-score for a battery which lasts 5,300 hours

The manager of 45 sales people examined their monthly expenditures on entertaining clients.He found that the mean amount was $237.50 with a standard deviation of $27.40.Assuming the data is bell-shaped,would a claim for the amount of $300 be considered unlikely? Why or why not?

What is the smallest measure of central tendency in a positively skewed distribution?

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: The police lieutenant in charge of the traffic division has reviewed the number of traffic citations issued per day by each of the 10 police officers in his division.The data were: 13,21,12,34,31,13,22,26,25,and 23. -What is the median number of citations issued per day?

The measure that examines the location of a data value relative to the mean of the distribution is called a z-score.

A correlation coefficient of zero indicates a lack of relationship between the two variables of interest.

Positive skewness results if a distribution is skewed to the left.

Which of the following statement is true?

Quartiles and percentiles are two of the most popular measures of dispersion.

Which one of the values below represents a lower quartile for the data set 23,24,21,and 20?

A sample of college students revealed their last month income as follows: $765,$680,$623,$980,$875,and $985.How many observations are below the median?

Since 1985,the daily temperature in Daytona Beach,Florida during spring break week has a mean of 74.6 degrees and a standard deviation of 2.2 degrees.Assuming that the distribution of temperatures is bell-shaped,how likely is it that the average daily temperature this year will be above 71 degrees? Explain.

According to the empirical rule,you expect 95% of the measurements to lie within the interval [71.60,99.48] whereas all the given measurements actually lie within this interval.Do your expectations agree with the provided data? If not,what conclusion can be drawn?

A large sample is selected from a bell-shaped distribution.The middle 99.7% of the sample data falls between 24.2 and 69.2.Estimate the sample mean and the sample standard deviation.

Find the IQR.

The Empirical rule is frequently applied as an interpretive guide to any mounded distribution.

Minitab,Excel,SPSS,SAS,and other statistical programs can be used to compute descriptive measures such as the sample covariance and the sample correlation coefficient.

What effect,if any,does subtracting 5 from every observation have on the sample mean and sample variance?

The measure that examines the location or position of a value relative to the mean of the distribution is called a: