1. For e ach variable, decide if the variable is qualitative or quantitative, discrete or continuous and decide the level of measurement (Nominal, Ordinal, Interval or Ratio).   

Consider the example: (1) At CUNY for the same undergraduate course credit foreign students pay a higher tuition rate than U.S. students. (2) Moreover, undergraduate students pay the same tuition for 15 (or even 18) credits per semester as they do for 12.

Find the correct statement about this example.

The grade point averages (GPAs) of a large population of college students are approximately normally distributed with mean 2.5 and standard deviation 0.7. If students possessing a GPA less than 1.75 are dropped from college, what percentage of the students will be dropped? (Round your answer to two decimal places.)

?? %

The width of bolts of fabric is normally distributed with mean 950 mm (millimeters) and standard deviation 10 mm.

(a) What is the probability that a randomly chosen bolt has a width between 943 and 959 mm? (Round your answer to four decimal places.)

What is the probability that a randomly chosen bolt has a width between 943 and 959 mm? (Round your answer to four decimal places.)

(b)

What is the appropriate value for C such that a randomly chosen bolt has a width less than C with probability 0.8749? (Round your answer to two decimal places.)

C =

Q) The age for COVID-19 patients in a country is normally distributed with mean 57.6 years and standard deviation 28 years. A COVID-19 patient was randomly selected from that country. Find the probability that this patient
(i) is below 50 years.
(ii) is between 30 and 75 years.
(iii) 5% of the patients are above k years old. Find k.
(b) The number of COVID-19 patients in 5 different countries are shown in the table below.

Country A B C D E

Number of patients 1006 112 1104 926 1852 Test at 10% significance level, if the number of COVID-19 patients is evenly distributed among the five countries.

(c) In 2019, 20% of the students at University X are from China. In a random sample of 500 university students selected recently, it is found that that 130 of them are from China. Test if there is an increase in the percentage of China students in University X at 3% significance level

The age for COVID-19 patients in a country is normally distributed with mean 57.6 years and standard deviation 28 years. A COVID-19 patient was randomly selected from that country. Find the probability that this patient
(i) is below 50 years.
(ii) is between 30 and 75 years.
(iii) 5% of the patients are above k years old. Find k.
(b) The number of COVID-19 patients in 5 different countries are shown in the table below.
Country A B C D E Number of patients 1006 112 1104 926 1852 Test at 10% significance level, if the number of COVID-19 patients is evenly distributed among the five countries.

(c) In 2019, 20% of the students at University X are from China. In a random sample of 500 university students selected recently, it is found that that 130 of them are from China. Test if there is an increase in the percentage of China students in University X at 3% significance level.

In a study of academic procrastination, the authors of a paper reported that for a sample of 441 undergraduate students at a midsize public university preparing for a final exam in an introductory psychology course, the mean time spent studying for the exam was 7.74 hours and the standard deviation of study times was 3.40 hours. For purposes of this exercise, assume that it is reasonable to regard this sample as representative of students taking introductory psychology at this university.

a) Construct a 95% confidence interval to estimate μ, the mean time spent studying for the final exam for students taking introductory psychology at this university. (Round your answers to three decimal places.)

(__________ , __________ )

b) The paper also gave the following sample statistics for the percentage of study time that occurred in the 24 hours prior to the exam.

n = 441      x = 43.78      s = 21.46

Construct a 90% confidence interval for the mean percentage of study time that occurs in the 24 hours prior to the exam. (Round your answers to three decimal places.)

(_________ , _________ )

Many states assess the skills of their students in various grades. One program that is available for this purpose is the National Assessment of Educational Progress (NAEP). We assumed that the NAEP U.S. history scores for twelfth-grade students are approximately Normal with the reported mean and standard deviation, N(295 , 33 ). For the twelfth-grade U.S. history scores, the following percentiles are reported:

Let's check that assumption. In addition to means and standard deviations, you can find selected percentiles for the NAEP assessments.

Use these percentiles to assess whether or not the NAEP U.S. history scores for twelfth-grade students are approximately Normal.

Use software to compute ( ±±0.01) the scores with N(295 , 33 ):