A “subliminal” message is below our threshold of awareness but may nonetheless influence us. A study looked at the effect of subliminal messages on math skills. Messages were flashed on a screen too rapidly to be consciously read. Twenty-eight students who had failed the mathematics part of the City University of New York Skills Assessment Test were randomly assigned to receive daily either a positive subliminal message (“Each day I am getting better in math”) or a neutral subliminal message (“People are walking on the street”). All students took the assessment test again at the end of the program, and the table below gives the data on each of the subjects’ scores before and after the program. Is there statistical evidence that the positive message brought about a greater improvement in math scores than the neutral message? Make no assumptions and show all work.
| Positive Message | ||
| Before | After | Difference |
| 18 | 24 | 6 |
| 18 | 25 | 7 |
| 21 | 33 | 12 |
| 18 | 29 | 11 |
| 18 | 33 | 15 |
| 20 | 36 | 16 |
| 23 | 34 | 11 |
| 23 | 36 | 13 |
| 21 | 34 | 13 |
| 17 | 27 | 10 |
| Neutral Message | ||
| Before | After | Difference |
| 18 | 29 | 11 |
| 24 | 29 | 5 |
| 20 | 24 | 4 |
| 18 | 26 | 8 |
| 24 | 38 | 14 |
| 22 | 27 | 5 |
| 15 | 22 | 7 |
| 19 | 31 | 12 |
| Ho: | |
| Ha: | |
| Exact P for F test: | |
| test-statistic: | |
| df: | |
| Exact P value for the test-statistic | |
| Conclusion relative to the hypothesis: | |
| ts= , df= ,P= |
Got the data by Excel
In: Math
Naive Bayes Theorem
See the dataset D in Table 1. It consists of clinical data about 14 patients. Using the data in D, determine the Naive Bayes classifier and predict the patients in Table 2. Then, compare with your ‘predicted’ ones with the ground-truth label (i.e., column ’Disease’) and report the accuracy P.
Table 1: Dataset D with clinical data of 14 patients
|
ID |
HBP |
BMI |
Drink |
Weight |
Disease |
|
1 |
“Yes” |
“Normal” |
“No” |
“Overweight” |
“Yes” |
|
2 |
“No” |
“Normal” |
“Yes” |
“Normal” |
“No” |
|
3 |
“No” |
“Critical” |
“No” |
“Overweight” |
“Yes” |
|
4 |
“No” |
“High” |
“Yes” |
“Overweight” |
“Yes” |
|
5 |
“Yes” |
“Critical” |
“Yes” |
“Obese” |
“Yes” |
|
6 |
“Yes” |
“High” |
“Yes” |
“Normal” |
“Yes” |
|
7 |
“No” |
“High” |
“No” |
“Obese” |
“No” |
|
8 |
“Yes” |
“Normal” |
“Yes” |
“Normal” |
“Yes” |
|
9 |
“Yes” |
“Critical” |
“No” |
“Obese” |
“Yes” |
|
10 |
“No” |
“Normal” |
“No” |
“Overweight” |
“No” |
|
11 |
“No” |
“Critical” |
“Yes” |
“Normal” |
“Yes” |
|
12 |
“Yes” |
“High” |
“No” |
“Overweight” |
“No” |
|
13 |
“Yes” |
“Normal” |
“Yes” |
“Overweight” |
“Yes” |
|
14 |
“Yes” |
“High” |
“No” |
“Obese” |
“No” |
Table 2: Test data with additional 5 patients
|
ID |
HBP |
BMI |
Drink |
Weight |
Disease |
|
15 |
“Yes” |
“Normal” |
“No” |
“Overweight” |
“Yes” |
|
16 |
“No” |
“Normal” |
“Yes” |
“Normal” |
“No” |
|
17 |
“No” |
“Critical” |
“No” |
“Overweight” |
“Yes” |
|
18 |
“No” |
“High” |
“Yes” |
“Overweight” |
“Yes” |
|
19 |
“Yes” |
“Critical” |
“Yes” |
“Obese” |
“Yes” |
In: Math
In a developing country, 19% of the entire population has
high
speed access to the internet. Random samples of size 200 are
selected from the country’s
population in order to estimate the proportion of the population
with high-speed internet
access.
a) What is the expected sample proportion? (Do not use the
CLT.)
b) What is the standard deviation of the sample proportion? (Do not
use the CLT.)
c) What is the probability that the sample proportion is (strictly)
less than 14%? (Do not
use the CLT.)
d) Use the Central Limit Theorem (CLT) to estimate the probability
that the sample
proportion is between 9% and 29%?
e) Use the CLT to estimate the value p such that the probability
that the sample propor
tion is above p is 90%.
Note : Please explain C in details
In: Math
It is estimated that approximately 8.17% Americans are afflicted with diabetes. Suppose that a certain diagnostic evaluation for diabetes will correctly diagnose 98% of all adults over 40 with diabetes as having the disease and incorrectly diagnoses 3% of all adults over 40 without diabetes as having the disease. a) Find the probability that a randomly selected adult over 40 does not have diabetes, and is diagnosed as having diabetes (such diagnoses are called "false positives"). b) Find the probability that a randomly selected adult of 40 is diagnosed as not having diabetes. c) Find the probability that a randomly selected adult over 40 actually has diabetes, given that he/she is diagnosed as not having diabetes (such diagnoses are called "false negatives"). (Note: it will be helpful to first draw an appropriate tree diagram modeling the situation)
In: Math
A new car dealer calculates that the dealership must average more than 4.5% profit on sales of new cars. A random sample of 81 cars yielded a sample mean of 4.97% profit and a sample standard deviation of 1.8%. Using a significance level of α = .05, does the sample data provide evidence to conclude that the dealership averages more than 4.5% profit on sales of new cars?
A. Yes, because the the sample mean is more than 4.5%.
B. Yes, because p = .0106 is less than .05.
C. No, because t = 2.35 is more than 1.645
D. No, because the p-value is less than the critical value
In: Math
Water specimens are taken from water used for cooling as it is being discharged from a power plant into a river. It has been determined that as long as the mean temperature of the discharged water is at most 150°F, there will be no negative effects on the river's ecosystem. To investigate whether the plant is in compliance with regulations that prohibit a mean discharge water temperature above 150°F, researchers will take 50 water specimens at randomly selected times and record the temperature of each specimen. The resulting data will be used to test the hypotheses
H0: μ = 150°F
versus
Ha: μ > 150°F.
(a) In the context of this example, describe Type I and Type II errors. (Select all that apply.)
A Type I error is not obtaining convincing evidence that the mean water temperature is greater than 150°F when in fact it is greater than 150°F.
A Type I error is obtaining convincing evidence that the mean water temperature is greater than 150°F when in fact it is (at most) 150°F.
A Type II error is obtaining convincing evidence that the mean water temperature is greater than 150°F when in fact it is (at most) 150°F.
A Type II error is not obtaining convincing evidence that the mean water temperature is greater than 150°F when in fact it is greater than 150°F.
A magazine collects data each year on the price of a hamburger in a certain fast food restaurant in various countries around the world. The price of this hamburger for a sample of restaurants in Europe in January resulted in the following hamburger prices (after conversion to U.S. dollars).
| 5.17 | 4.93 | 4.09 | 4.67 | 5.22 | 4.69 |
| 4.15 | 4.97 | 5.13 | 5.53 | 5.36 | 4.60 |
The mean price of this hamburger in the U.S. in January was $4.61. For purposes of this exercise, assume it is reasonable to regard the sample as representative of these European restaurants. Does the sample provide convincing evidence that the mean January price of this hamburger in Europe is greater than the reported U.S. price? Test the relevant hypotheses using
α = 0.05.
(Use a statistical computer package to calculate the P-value. Round your test statistic to two decimal places and your P-value to three decimal places.)
| t | = | |
| P-value | = |
Medical research has shown that repeated wrist extension beyond 20 degrees increases the risk of wrist and hand injuries. Each of 24 students at a university used a proposed new computer mouse design. While using the mouse, each student's wrist extension was recorded. Data consistent with summary values given in a paper are given. Use these data to test the hypothesis that the mean wrist extension for people using this new mouse design is greater than 20 degrees. (Use
α = 0.05.
Use a statistical computer package to calculate the P-value. Round your test statistic to two decimal places and your P-value to three decimal places.)
| 26 | 28 | 25 | 27 | 26 | 24 | 24 | 25 | 25 | 25 | 24 | 28 |
| 22 | 24 | 25 | 28 | 26 | 27 | 31 | 24 | 28 | 26 | 26 | 24 |
| t | = | |
| P-value | = |
In: Math
Each round of game played by a gambler is either a win with probability p or a loss with probability 1 − p. If the round is a win, then a random amount of money having an exponential distribution with rate λ will be awarded to the gambler. If the round is a loss, then he loses everything that had been accumulated up to that time and cannot play any additional rounds. After a win round, the gambler can either choose to quit and keep whatever has been won or can choose to play another round. Suppose that a gambler plans to continue playing until either his total winnings exceeds t or a loss occurs.
(a) What is the expectation of N, the number of winning rounds that it would take until his fortune 1 exceeds t?
(b) What is the probability he will successfully reach a fortune of at least t?
In: Math
Not handwriting answer, please
In a word document, please answer the following questions:
Course Introduction of Biostatistics
Define the following terms:
correlation coefficient
scatter plot
bivariate relationship
Provide an example where the outlier is more important to the
research than the other observations?
Identify when to use Spearman’s rho.
In: Math
In: Math
In a study of the accuracy of fast food drive-through orders, Restaurant A had 231
accurate orders and
74
that were not accurate.a. Construct a
95%
confidence interval estimate of the percentage of orders that are not accurate.b. Compare the results from part (a) to this
95%
confidence interval for the percentage of orders that are not accurate at Restaurant B:
0.2160 <p<0.319
What do you conclude?
a. Construct a
95%
confidence interval. Express the percentages in decimal form.
nothing less than<pless than<nothing
(Round to three decimal places as needed.)
In: Math
To navigate on Lake Latte (fed by the Decaf and the Vanilla
Rivers) at least two of the three
radio navigation beacons must be working. If the probability that a
beacon is working is
p and the operational status of each station is independent of the
other two, what is the
probability of being able to navigate on the lake? What is the
probability that beacon #2 is
working if navigation on the lake is possible?
In: Math
In any given year, one in three Americans over the age of 65 will experience a fall. If you have three living grandparents over the age of 65, and assuming that the probability of a fall for each grandparent is independent:
a. What is the probability that none of the three grandparents will experience a fall? Provide your answer as a decimal between 0 and 1. Hint: Your sample size is 3, what is the number of successes.
b. What is the probability that one or more grandparents will experience a fall? Provide your answer as a decimal between 0 and 1.
In: Math
1. Given an equilateral triangle ABC with a side of 5 cm. Find the probability that a point taken at random will be located from point A at a distance greater than 2 cm.
2. There are two boxes: inside the first 10 white and 15 black balls, inside the second 10 white and 10 black balls. 5 balls are transferred from the first box to the second and then one ball is removed from the second box at random, what is the probability that it is white?
Thanks Sir )
In: Math
2.38 Baggage fees: An airline charges the
following baggage fees: $25 for the first bag and an extra $35 for
the second. Suppose 54% of passengers have no checked luggage, 34%
have only one piece of checked luggage and 12% have two pieces. We
suppose a negligible portion of people check more than two
bags.
a) The average baggage-related revenue per passenger is:
$ (please round to the nearest cent)
b) The standard deviation of baggage-related revenue is:
$ (please round to the nearest cent)
c) About how much revenue should the airline expect for a flight of
120 passengers? $ (please round to the nearest
dollar)
In: Math
In the article “Explaining an Unusual Allergy,” appearing on the
Everyday Health Network, Dr. A Feldweg explained that allergy to
sulfites is usually seen in patients with asthma. The typical
reaction is a sudden increase in asthma symptoms after eating a
food containing sulfites. Studies are performed to estimate the
percentage of the nation’s 10 million asthmatics who are allergic
to sulfites. In one survey, 38 of 500 randomly selected U.S.
asthmatics were found to be allergic to sulfites.
(Source: Elementary Statistics, Weiss, 8th Edition)
If you were to construct a 98% confidence interval for the proportion of all U.S. asthmatics who are allergic to sulfites, what is the margin of error used to calculate the interval? (use the standard error found in problem 1, round your critical value to the hundredths place, and round the margin of error to the thousandths place)
In: Math