As the director of the local Boys Club, you have claimed for years that membership in your club reduces juvenile delinquency. Now a cynical member of your funding agency has demanded proof of your claim. Random samples of members and nonmembers are gathered and interviewed with respect to their involvement in delinquent activities. Each respondent is asked to enumerate the number of delinquent acts he has engaged in over the past year. The average numbers of admitted acts of delinquency are reported below. What can you tell the funding agency? $$ \begin{array}{cc} \hline \hline \begin{array}{c} \text { Sample 1 } \\ \text { (Members) } \end{array} & \begin{array}{c} \text { Sample 2 } \\ \text { (Nonmembers) } \end{array} \\ \hline \bar{X}_{1}=10.3 & \bar{X}_{2}=12.3 \\ s_{1}=2.7 & s_{2}=4.2 \\ N_{1}=40 & N_{2}=55 \\ \hline \end{array} $$
Added by Peggy C.
Step 1
The average number of admitted acts of delinquency for members is 10.3, while for nonmembers it is 12.3. This means that, on average, members of the club commit fewer delinquent acts than nonmembers. The standard deviation (s) for members is 2.7 and for Show more…
Show all steps
Close
Your feedback will help us improve your experience
Sri K and 52 other Intro Stats / AP Statistics educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
As the director of the local Boys Club, you have claimed for years that membership in your club reduces juvenile delinquency. Now a cynical member of your funding agency has demanded proof of your claim. Fortunately, your local sociology department is on your side and springs to your aid with student assistants, computers, and hand calculators at the ready. Random samples of members and nonmembers are gathered and interviewed with respect to their involvement in delinquent activities. Each respondent is asked to enumerate the number of delinquent acts he has engaged in over the past year. The results are in and reported here (the average number of admitted acts of delinquency). What can you tell the funding agency?
Keondre P.
An insurance company wants to analyze the claims for damage due to fire on its household content's policies. The values for a sample of 50 claims in Rupees are shown in Table $3.17$.$$ egin{array}{l} ext { Table 3.17 Data for Problem } 3.9\ egin{array}{l|l|l|l|l|l|l|l|l|l} hline 57000 & 115000 & 119000 & 131000 & 152000 & 167000 & 188000 & 190000 & 197000 & 201000 \ hline 206000 & 209000 & 213000 & 217000 & 221000 & 229000 & 247000 & 250000 & 252000 & 253000 \ hline 257000 & 257000 & 258000 & 259000 & 260000 & 261000 & 262000 & 263000 & 267000 & 271000 \ hline 277000 & 285000 & 287000 & 305000 & 307000 & 309000 & 311000 & 313000 & 317000 & 321000 \ hline 322000 & 327000 & 333000 & 351000 & 357000 & 371000 & 399000 & 417000 & 433000 & 499000 \ hline end{array} end{array} $$ $$ egin{array}{l} ext { Table } 3.18 ext { Grouped frequency distribution of the data given in Table } 3.17\ egin{array}{l|l|l|l|l|l|l|l|l|l|} hline egin{array}{l} ext { Claim size } \ ext { (In 1000's } \ ext { of Rupees) } end{array} & 50-99 & 100-149 & 150-199 & 200-249 & 250-299 & 300-349 & 350-399 & 400-449 & 450-500 \ hline ext { Frequency } & 1 & 3 & 5 & 8 & 16 & 10 & 4 & 2 & 1 \ hline end{array} end{array} $$ 1. What is the range of the above data? 2. Draw a bar graph for Table $3.18$. 3. For the data given in Table $3.18$ if instead of equal-sized groups, we had a single group for all value below 250 , how would this bar be represented? 4. Calculate the mean, median, mode, and sample geometric mean. 5. Calculate the sample standard deviation and sample variance. 6. Calculate the coefficient of variation.
Jerelyn N.
A shareholders' group, in lodging a protest, claimed that the mean tenure for a chief executive officer (CEO) was at least nine years. A survey of companies reported in The Wall Street Journal found a sample mean tenure of $\overline{x}=7.27$ years for CEOs with a standard deviation of $s=6.38$ years (The wall Street Journal, January $2,2007 )$ a. Fomulate hypotheses that can be used to challenge the validity of the claim made by the shareholders' group. b. Assume 85 companies were included in the sample. What is the $p$ -value for your hypothesis test? c. At $\alpha=.01,$ what is your conclusion?
Recommended Textbooks
Elementary Statistics a Step by Step Approach
The Practice of Statistics for AP
Introductory Statistics
Transcript
Watch the video solution with this free unlock.
EMAIL
PASSWORD