Choose the best answer. Justify for full credit. (a) UMUC STAT Club wanted to es
ID: 3324949 • Letter: C
Question
Choose the best answer. Justify for full credit. (a) UMUC STAT Club wanted to estimate the study hours of STAT 200 students. One STAT 200 section was randomly selected and all students from that section were asked to fill out the questionnaire. This type of sampling is called: (i) cluster (ii) convenience (iii) systematic (iv) stratified (b) A study was conducted at a local college to analyze the trend of average GPA of all students graduated from the college. According to the Registrar, the average GPA for students with economics major from the class of 2016 is 3.5. The value 3.5 is a (i) statistic (ii) parameter (iii) cannot be determined (c) The hotel ratings are usually on a scale from 0 star to 5 stars. The level of this measurement is (i) interval (ii) nominal (iii) ordinal (iv) ratio (d) 500 students took a chemistry test. You sampled 100 students to estimate the average score and the standard deviation. How many degrees of freedom were there in the estimation of the standard deviation? (i) 99 (ii) 100 (iii) 499 (iv) 500 (e) You choose an alpha level of 0.01 and then analyze your data. What is the probability that you will make a Type I error given that the null hypothesis is true? (i) 0.025 (ii) 0.05 (iii) 0.01 (iv) 0.10
Explanation / Answer
One STAT 200 section was randomly selected and all students from that section were asked to fill out the questionnaire. This type of sampling is called cluster sampling . In cluster sampling we select groups ( or clusters) randomly and study all the units in the selected clusters.
(b) A study was conducted at a local college to analyze the trend of average GPA of all students graduated from the college. According to the Registrar, the average GPA for students with economics major from the class of 2016 is 3.5. The value 3.5 is a (i) statistic (ii) parameter (iii) cannot be determined .
The correct option is ii) Parameter. Because 3.5 is the average of GPA for students with economics major from the class of 2016.
(c) The hotel ratings are usually on a scale from 0 star to 5 stars. The level of this measurement is (i) interval (ii) nominal (iii) ordinal (iv) ratio
The correct option is iii) ordinal. Because here difference and ratio of the ranks are meaningless, but order is meaningful measure.
(d) 500 students took a chemistry test. You sampled 100 students to estimate the average score and the standard deviation. How many degrees of freedom were there in the estimation of the standard deviation? (i) 99 (ii) 100 (iii) 499 (iv) 500
The correct option is 99
Degrees of freedom = sample size - 1 = 100 - 1 = 99
(e) You choose an alpha level of 0.01 and then analyze your data. What is the probability that you will make a Type I error given that the null hypothesis is true? (i) 0.025 (ii) 0.05 (iii) 0.01 (iv) 0.10
the correct option is iii) 0.01. Because probability of making the type I error is same as level of significance