|
31.9 |
32.1 |
39.1 |
36.6 |
24.2 |
|
38.8 |
21.9 |
36.2 |
26.9 |
35.5 |
|
33.8 |
28.0 |
35.4 |
31.9 |
29.6 |
|
27.7 |
37.1 |
36.8 |
36.9 |
28.5 |
|
35.4 |
28.7 |
30.5 |
34.3 |
34.2 |
|
35.9 |
30.0 |
32.6 |
33.0 |
35.7 |
|
28.7 |
33.8 |
30.2 |
41.1 |
25.3 |
Recently a similar study was conducted. The results are shown below.
|
44.7 |
55.0 |
49.4 |
51.3 |
45.4 |
|
47.2 |
41.1 |
42.2 |
54.8 |
50.0 |
|
47.1 |
51.0 |
43.0 |
42.9 |
49.8 |
|
51.5 |
52.8 |
49.6 |
39.0 |
48.6 |
|
54.6 |
44.7 |
47.2 |
40.2 |
47.9 |
|
58.0 |
46.7 |
52.0 |
48.7 |
54.4 |
|
45.5 |
41.1 |
46.6 |
45.6 |
50.0 |
At α = 0.05, do middle school boys study more today than in 1981? You can assume that the population approaches a normal distribution.
In: Statistics and Probability
I am going to study gender differences and scores on the spelling test. Ind variable: Gender (Male or female) Dep variable: spelling test score Null: There is no difference between males and females on the spelling test. Directional: Boys will score higher than girls on the spelling test. Now, create a study.
In: Statistics and Probability
Statistical Significance. In an experiment testing a method of gender selection intended to increase the likelihood that a baby is a girl, 1000 couples give birth to 501 girls and 499 boys. An analyst argues that this fails to provide evidence that the method has any effect, because the probability of getting these results by chance is 0.487, or almost 50%.
In: Statistics and Probability
Question 3: A freshman class consists of 6 students, 3 of which are girls. The class needs to select a committee of 2 to represent them in the student senate.
(1) Write the sample space of this experiment.
(2) Calculate the probability of a committee of two boys. (3)
Calculate the probability of one boy and one girl.
In: Math
A) If four babies are born in a given hospital on the
same day, what is the probability that all four will be boys?
B) if four babies are born in a given hospital on the same day,
what is the probability that 3 will be girls and 1 will be a
boy?
C) You flip a coin twice what is the probability that it lands on
heads once and tails one?
In: Math
Baird County maintains an investment trust fund for the School
District and the Town of Bairdville (separate governments).
Presented below is the preclosing trial balance for the investment
trust fund, a private-purpose trust fund.
| Trial Balance—December 31, 2017 | Debits | Credits | ||||
| Accrued Interest Receivable | $ | 23,000 | ||||
| Cash | 38,300 | |||||
| Deposits—School District | $ | 459,600 | ||||
| Deposits—Town of Bairdville | 336,200 | |||||
| Decrease in Fair Value of Investments (bonds) | 15,300 | |||||
| Interest Income | 91,800 | |||||
| Investments—Corporate Bonds | 1,576,000 | |||||
| Investments—U.S. Treasury Securities | 1,530,000 | |||||
| Net Position held in trust—School District (Jan. 1) | 1,530,000 | |||||
| Net Position held in trust—Town of Bairdville (Jan. 1) | 765,000 | |||||
| $ | 3,182,600 | $ | 3,182,600 | |||
Investment earnings are distributed among the School District and
Town in proportion to the amounts contributed (two-thirds to the
School District and one-third to the Town).
Required:
Prepare the year-end closing entries and a Statement of Changes in
Fiduciary Net Position for the year ended December 31, 2017.
In: Accounting
Baird County maintains an investment trust fund for the School
District and the Town of Bairdville (separate governments).
Presented below is the preclosing trial balance for the investment
trust fund, a private-purpose trust fund.
| Trial Balance—December 31, 2017 | Debits | Credits | ||||
| Accrued Interest Receivable | $ | 23,000 | ||||
| Cash | 38,300 | |||||
| Deposits—School District | $ | 459,600 | ||||
| Deposits—Town of Bairdville | 336,200 | |||||
| Decrease in Fair Value of Investments (bonds) | 15,300 | |||||
| Interest Income | 91,800 | |||||
| Investments—Corporate Bonds | 1,576,000 | |||||
| Investments—U.S. Treasury Securities | 1,530,000 | |||||
| Net Position held in trust—School District (Jan. 1) | 1,530,000 | |||||
| Net Position held in trust—Town of Bairdville (Jan. 1) | 765,000 | |||||
| $ | 3,182,600 | $ | 3,182,600 | |||
Investment earnings are distributed among the School District and
Town in proportion to the amounts contributed (two-thirds to the
School District and one-third to the Town).
Required:
Prepare the year-end closing entries and a Statement of Changes in
Fiduciary Net Position for the year ended December 31,
2017.
In: Accounting
The population of a small town was 20,000 on January 1st, 2010 and has grown at a rate of about 2% per year since then. Next year, the local high school is closing and this is likely to affect the population of the town as people move away to towns with more schools.
(a) Write down a model of the population of the town for the years 2010 to 2019. Carefully define any variables you use and state any assumptions you make.
(b) Calculate the expected size of the population on January 1st 2020.
(c) The town council wants to work out what will happen to the population once the school closes. They are considering three possible effects:
• Half the families with children of high school age will move out of town immediately. There are 1200 people in families with children of high school age in 2019.
• 10% of the population will move away each year, starting in 2020, because of decreasing opportunities for work in the town resulting from the school closure.
• 100 people who do not like children will move to the town each year once the school has closed and families start to leave. Explain how you would modify the model you wrote down in part (a) to model the population from 2020 onwards. Take account of each of the three effects. Carefully state any assumptions you make.
(d) Use dfield and your model from part (c) to estimate the size the population of the town on January 1st 2025. Include an appropriate printout from dfield to support your answer.
(e) What do you think will happen to the population of the town in the long term? Include an appropriate printout from dfield to support your answer.
In: Statistics and Probability
(4) The sample space that describes all three-child families
according to the genders of the children with respect to birth
order is In the experiment of selecting a three-child family at
random, compute each of the following probabilities, assuming all
outcomes are equally likely.
S = {bbb, bbg, bgb, bgg, gbb, gbg, ggb, ggg}
a. The probability that the family has at least two boys.
b. The probability that the family has at least two boys, given
that not all of the children are girls.
c. The probability that at least one child is a boy.
d. The probability that at least one child is a boy, given that the
first born is a girl.
In: Statistics and Probability
4. The CDC publishes charts on Body Mass Index (BMI) percentiles for boys and girls of different ages. Based on the chart for girls, the mean BMI for 6-year-old girls is listed as 15.2 kg/m2. The data from which the CDC charts were developed is old and there is concern that the mean BMI for 6-year old girls has increased. The BMIs of a random sample of 30 6-year-old girls are given below.
|
24.5 |
16.3 |
15.7 |
20.6 |
15.3 |
14.5 |
14.7 |
15.7 |
14.4 |
13.2 |
|
16.3 |
15.9 |
16.3 |
13.5 |
15.5 |
14.3 |
13.7 |
14.3 |
13.7 |
16.0 |
|
14.2 |
17.3 |
19.5 |
22.8 |
16.4 |
15.4 |
18.2 |
13.9 |
17.6 |
15.5 |
a. State null and alternative hypotheses relevant to this situation.
b. Calculate the sample mean and standard deviation.
c. Since the sample size is relatively large, use s in place of σ and calculate the value of the z-test statistic. Then calculate the p-value.
d. Based on your answer to (c), do the sample data provide sufficient evidence that the mean BMI for 6-year-old girls has increased? Explain
In: Statistics and Probability