Question

In: Math

A large school district claims that 80% of the children are from low-income families. 130 children...

A large school district claims that 80% of the children are from low-income families. 130 children from the district are chosen to participate in a community project. Of the 130 only 72% are from low-income families. The children were supposed to be randomly selected. Do you think they really were?

a. The null hypothesis is that the children were randomly chosen. This translates into drawing times

Processing your submission ...

 Tries 0/3

at random
with replacement
without replacement

Processing your submission ...

 Tries 0/1

from a null box that contains

b.
130 tickets, 72% marked "1" and 28% marked "0"
Thousands of tickets, 80% marked "1" and 20% marked "0"
Thousands of tickets marked either "1" or "0", but the exact percentages of each are unknown and estimated from our sample.
5 tickets, 1 marked "1" and 4 marked "0"

Processing your submission ...

 Tries 0/3

c. What is the expected value of the percent of 1's in the draws? (Don't type in the % sign)

%

Processing your submission ...

 Tries 0/3

d. What is the SD of the null box? (Note: We don't have to estimate the SD of the box from the sample SD because we can compute it directly from the percent of 1's in the null box. This is why we never use a t-test for problems that can be translated into 0-1 boxes.)

Processing your submission ...

 Tries 0/3

e. What is the standard error of the % of 1's in the draws? (Round to 2 decimal places.) %

Processing your submission ...

 Tries 0/3

f. What is the value of the test statistic z? (Round answer to 2 decimal places.)

Processing your submission ...

 Tries 0/3

g. What is the p-value? Click here to view the normal table
%

Processing your submission ...

 Tries 0/3

h. What do you conclude?
There is very strong evidence to reject the null, and conclude that the children were not randomly chosen.
We cannot reject the null, it's plausible the children were randomly chosen.

Solutions

Expert Solution

Let p denotes the true proportion of children who are from low-income families.

h) Conclusion : There is very strong evidence to reject the null, and conclude that the children were not randomly chosen.

milcah answered 8 months ago
Next > < Previous

Related Solutions

The mayor of a large city claims that 30 % of the families in the city...
The mayor of a large city claims that 30 % of the families in the city earn more than $ 100,000 per year; 60 % earn between $ 30,000 and $ 100,000 (inclusive); 10 % earn less than $ 30,000 per year. In order to test the mayor’s claim, 285 families from the city are surveyed and it is found that: 100 of the families earn more than $ 100,000 per year; 150 of the families earn between $ 30,000...
The mayor of a large city claims that 25 % of the families in the city...
The mayor of a large city claims that 25 % of the families in the city earn more than $ 100,000 per year; 55 % earn between $ 30,000 and $ 100,000 (inclusive); 20 % earn less than $ 30,000 per year. In order to test the mayor’s claim, 285 families from the city are surveyed and it is found that: 90 of the families earn more than $ 100,000 per year; 135 of the families earn between $ 30,000...
The mayor of a large city claims that 25 % of the families in the city...
The mayor of a large city claims that 25 % of the families in the city earn more than $ 100,000 per year; 55 % earn between $ 30,000 and $ 100,000 (inclusive); 20 % earn less than $ 30,000 per year. In order to test the mayor’s claim, 285 families from the city are surveyed and it is found that: 90 of the families earn more than $ 100,000 per year; 135 of the families earn between $ 30,000...
How is buying a house in a good school district like sending children to a private school?
How is buying a house in a good school district like sending children to a private school?Fill in blanks A-D in the following table.Units of Good ConsumedTotal Utility (Utils)Marginal Utility (Utils)11010219A?3B?8433C?535D?
In a survey of 99 families in Karachi, 45 were low income families who at some...
In a survey of 99 families in Karachi, 45 were low income families who at some point in time were involved in electricity theft. 13 were low income families who never did any violation. 16 were high income families who involved in electricity theft, and 25 high income families never did any violation. If One of these subject is randomly selected, what is the probability of: i. Low income families or someone who did electricity theft. ii. Low income families...
A sample of 25 seniors from a large metropolitan area school district had a mean Math...
A sample of 25 seniors from a large metropolitan area school district had a mean Math SAT score of 450. Suppose we know that the standard deviation of the population of Math SAT scores for seniors in the district is 100. A 90% confidence interval for the population mean SAT score for the population of seniors is used. Which of the following would produce a confidence interval with a smaller margin of error?                                                                                                    (2) Using a sample of 100...
(8 pts) The superintendent of a large school district speculated that high school students involved in...
(8 pts) The superintendent of a large school district speculated that high school students involved in extracurricular activities had a lower mean number of absences per year than high school students not in extracurricular activities. She generated a random sample of students from each group and recorded the number of absences each student had in the most recent school year. The data are listed below. Test the superintendent’s claim at the α=.01 significance level. [To receive full credit, your response...
The superintendent of a large school district speculated that high school students involved in extracurricular activities...
The superintendent of a large school district speculated that high school students involved in extracurricular activities had a lower mean number of absences per year than high school students not in extracurricular activities. She generated a random sample of students from each group and recorded the number of absences each student had in the most recent school year. The data are listed below. Test the superintendent’s claim at the α=.01 significance level. [To receive full credit, your response should be...
Suppose we want to estimate the average weight of children in a particular school district. The...
Suppose we want to estimate the average weight of children in a particular school district. The district contains 15 elementary schools, 10 middle schools, and 2 high schools. For each of the following approaches, select the best description of the sampling design, and identify whether the sampling scheme ensures that the probability of being included is necessarily the same for every student. A. List all the students in the school district. Average the weights of every 50th student on the...
It is generally believed that nearsightedness affects about 15% of children. A school district gives vision...
It is generally believed that nearsightedness affects about 15% of children. A school district gives vision tests to 111 incoming kindergarten children. Use the empirical rule (68%-95%-99.7% Rule) to determine what proportion of nearsighted children we might expect to see in samples of 111 children (I'm not looking for the number of children). Assume conditions are met! No need to draw the model, though if you find it easier to do so you may draw it by hand and attach...
ADVERTISEMENT
Subjects
ADVERTISEMENT
Latest Questions
ADVERTISEMENT