DB Week #5

b) A small-town mechanic says that 8% his customers come in for an oil change. When 1000 samples were drawn from his records, it was found that 6.5% of these came in for an oil change. What is the target population? Does the value 8% refer to the parameter or to the statistic? Is the value 6.5% a parameter or a statistic? i. ii. iii.

A simple random sample of 8 employees of a corporation provided the following information. Employee Age Gender 1 2 3 21 37 26 W M W 4 5 6 7 8 44 48 50 25 22 W W M M M (a) Determine the point estimate for the average age of all employees. (b) What is the point estimate for the standard deviation of the population? (Round your answer to four decimal places.) (c) Determine a point estimate for the proportion of all employees who are female.

Each of a sample of 176 residents selected from a small town is asked how much money he or she spent last week on state lottery tickets. 130 of the residents responded with $0. The mean expenditure for the remaining residents was $21. The largest expenditure was $210. Step 5 of 5: What proportion of the sample did not purchase any lottery tickets? Express your answer as a simplified fraction or as a value rounded to one decimal place.

Suppose you select a random sample of 16 students from a population that has  mean of µ = 75 and standard deviation of ơ = 20. You want to know what would be considered  a ‘typical’ sample mean for a sample of n = 16. To answer your question, you compute the two  sample means that define the middle 95% of the distribution of sample means. Show your  work, sketch the distribution, and shade in the area of interest. Hint: Sample means that are in  the extreme 5% of the distribution (2.5% in each tail of the distribution) are considered ‘atypical’ or ‘extreme.’

Supposed a study using a random sample of postgraduate students in Sydney found that the average amount of time spent using a mobile phone per day is 5.5 hours. Indicate whether the quantity described above is a population parameter or a sample statistic, and write down the notation.      Hints: You may type in how you read the notation, instead of using the symbol itself. E,g. you can write "mu" or "xbar" or "phat" or "rho" or "sigma" for the Greek alphabet or special symbol.

For 0.9588Y = 933.36 + 475, where did you guys get the 475 from?

The birthweight (in kg) of 55 babies are tabulated in the frequency distribution below: Birthweight (kg) Class Midpoint Frequency M (1– 1.5| (1.5-2 1.25 6. 1.75 10 (2- 2.5) 2.25 1 (2.5-3) 2.75 15 10 (3-3.5] 3.25 3. (3.5- 4) 3.75 55 Total Calculate the relative frequency of the class interval (2 - 2.5).

A study conducted at Virginia Commonwealth University in Richmond indicates that many older individuals can shed insomnia through psychological training. A total of 63 insomnia sufferers averaging age 67 years old completed eight weekly sessions of cognitive-behavior therapy. After the therapy, 31 participants enjoyed a substantially better night's sleep. Calculate the sample proportion of insomnia sufferers who did not enjoy a better night's sleep after the therapy. Round your answer to three decimal places, if necessary.

Suppose you apply an estimator to sample data and you get an estimate of 5 forwhatever sample you draw from the population. Is this estimator the most efficient because itsvariance is zero? Why or why not?

A statistics teacher wants to see if there is any difference in the performance of students on the final exam if she gives them orange jelly beans before the exam. She has a theory that orange jelly beans will change the results, but she isn't sure in which direction. She knows that the population mean score on the exam when students do not have orange jelly beans is 85 and that exam scores have an approximately symmetric distribution. She gives orange jelly beans to 25 randomly selected students and finds that these students had a sample mean score of 88 with a sample standard deviation of 5. She wants to have 99% confidence in her result.

Why can we not use first differences when we have independent cross sections in two years (as opposed to panel data)?

A courier service company wishes to estimate the proportion of people in various states that will use its services.  Suppose the true proportion is 0.05 . If 273 are sampled, what is the probability that the sample proportion will differ from the population proportion by less than 0.03 ? Round your answer to four decimal places.

Each of a sample of 176 residents selected from a small town is asked how much money he or she spent last week on state lottery tickets. 130 of the residents responded with $0. The mean expenditure for the remaining residents was $21. The largest expenditure was $210. Step 3 of 5: What is the mode of the data?

Problems-2: The following data shows birth weights (oz) from seven consecutive deliveries at the Johns Hopkins Hospital in April 2019. 121 138 32 100 58 64 a) Calculate the sample mean birth weight: =74 b) Calculate the sample median birth weight: =64 c) Calculate the sample standard deviation of these birth weights: =48.06593 d) Suppose this is a representative sample of births in a given year at Johns Hopkins. Suppose, instead of a sample of seven values, we have a sample of 100 birth weights. How should the mean, median, and standard deviation of this sample compare to the same statistics for the sample of seven birth weights?

PLEASE ANSWER CORRECTLY FULLY MAKE SURE THE ANSWER IS 100% RIGHT  NO MISTAKES PLEASE

Zip Code, Age and Number of Dogs by Person in Petland Person Zip Code Number Age of Dogs Ann 402 20 0 Bill 805 35 55 2 Carmelo 805 40 5 Dan 402 50 1 Eric 402 20 20 Ferdinand 402 35 55 3 3 Gert 402 20 2 Homer 402 20 0 In-choi 805 100 3 Jimmy 805 60 1

A rectangle is a four-sided figure that has two sets of parallel sides, so that we have two sides of one length and two sides of another length; a square is just a special case of a rectangle in which all four sides are the same length. Therefore, the procedure for calculating area is the same no matter whether we are dealing with a rectangle or a square. The area of a rectangle is calculated as follows: Area = base x height = b × h In this formula, the base is the width of the rectangle and the height is simply how tall the rectangle Is. For example, if we have a rectangle that is 20 centimeters wide and 10 centimeters tall, its area can be calculated as follows: Area = 20 cm x 10 cm = 200 cm² Note the superscript '2' In our answer; this is because we have multiplied centimeters by centimeters. In economics, we are more likely to be dealing with quantities bought or sold and prices, so don't worry about it too much for our discussion. The area of a triangle A triangle is really just a…

A rectangle is a four-sided figure that has two sets of parallel sides, so that we have two sides of one length and two sides of another length; a square is just a special case of a rectangle in which all four sides are the same length. Therefore, the procedure for calculating area is the same no matter whether we are dealing with a rectangle or a square. The area of a rectangle is calculated as follows: Area = base x height = b × h In this formula, the base is the width of the rectangle and the height is simply how tall the rectangle Is. For example, if we have a rectangle that is 20 centimeters wide and 10 centimeters tall, its area can be calculated as follows: Area = 20 cm x 10 cm = 200 cm² Note the superscript '2' In our answer; this is because we have multiplied centimeters by centimeters. In economics, we are more likely to be dealing with quantities bought or sold and prices, so don't worry about it too much for our discussion. The area of a triangle A triangle is really just a…

A rectangle is a four-sided figure that has two sets of parallel sides, so that we have two sides of one length and two sides of another length; a square is just a special case of a rectangle in which all four sides are the same length. Therefore, the procedure for calculating area is the same no matter whether we are dealing with a rectangle or a square. The area of a rectangle is calculated as follows: Area = base x height = b × h In this formula, the base is the width of the rectangle and the height is simply how tall the rectangle Is. For example, if we have a rectangle that is 20 centimeters wide and 10 centimeters tall, its area can be calculated as follows: Area = 20 cm x 10 cm = 200 cm² Note the superscript '2' In our answer; this is because we have multiplied centimeters by centimeters. In economics, we are more likely to be dealing with quantities bought or sold and prices, so don't worry about it too much for our discussion. The area of a triangle A triangle is really just a…

A rectangle is a four-sided figure that has two sets of parallel sides, so that we have two sides of one length and two sides of another length; a square is just a special case of a rectangle in which all four sides are the same length. Therefore, the procedure for calculating area is the same no matter whether we are dealing with a rectangle or a square. The area of a rectangle is calculated as follows: Area = base x height = b × h In this formula, the base is the width of the rectangle and the height is simply how tall the rectangle Is. For example, if we have a rectangle that is 20 centimeters wide and 10 centimeters tall, its area can be calculated as follows: Area = 20 cm x 10 cm = 200 cm² Note the superscript '2' In our answer; this is because we have multiplied centimeters by centimeters. In economics, we are more likely to be dealing with quantities bought or sold and prices, so don't worry about it too much for our discussion. The area of a triangle A triangle is really just a…

A10

Taubman et al., (2014) used data collected in the Portland, OR metro area to study the Impact Medicaid on emergency department (ED) use. The figure below shows the percent of respondents who have been to the ED at all (left hand side of the figure) and the average number of ED visits (right hand side of the figure). The dark blue bars represent the mean for the control group, and the light blue bars add in the "Medicaid" effect found in the paper. The black "capped" bar represents the confidence interval for the Medicaid effect. Percent with Any Visits 50 €30 20 10 O Any O O Any and Total ED Use Emergency Department Data Control Mean Control Mean plus Medicaid Effect Cl for Medicaid Effect The results above imply that the price elasticity of demand for emergency department use is Number of Visits perfectly inelastic not perfectly inelastic perfectly elastic

2 3 Lunch Spending ($) = x; 28 10 1 15 5 8 606 7 10 618 Z-Scores

2x+3z = 5 and 3x+2z = 5. The value of both x and z is A/

Please don't provide answer in image format thank you.

If the E(u|X) does not equal 0.   How can this assumption be relaxed if the sample size grows infinitely?

Manufacturers of tires report that car tires should be able to last an average of 50,000 miles. A new tire company produces a different type of tread and tests 100 randomly selected tires. This sample of 100 tires lasted an average of 51,500 miles. Assuming the new type of tread does not improve the mileage of the tire, 200 sample means were simulated and displayed on the dotplot. Simulated Tire Mileage +++ +++H 47,000 48,000 49,000 50,000 51,000 52,000 53,000 Mean mileage Using the dotplot and the sample mean mileage, is there convincing evidence that the new type of tread improves the mileage of the tire? Yes, because a mean mileage of 51,500 or more occurred only 14 out of 200 times, the mean mileage is statistically significant. There is convincing evidence the new type of tire tread improves mileage of the tire. Yes, because a mean mileage of 51,500 or less occurred 186 out of 200 times, the mean mileage is statistically significant. There is convincing evidence the new type of…