Statistics Questions: Questions 1 - 8: 1. Compare the formula values to the Desc

ID: 2906771 • Letter: S

Question

Statistics Questions: Questions 1 - 8:

1. Compare the formula values to the Descriptive Statistics table values for mean, median, mode, variance, and standard deviation - why are they the same?

2. Explain the meaning of the 25th and 75th percentiles in the context of this data set.

3. Find the Interquartile Range and show the math calculations and formula used.

4. What is the range of all the data? Show your calculation to show that the Data Analysis table is correct.

5. Calculate the z-score for the smallest piece of Nitrate data - show your calculations using the formula and see textbook page 113 to explain why x = 0 ppm is or is not an unusual value.

6. Calculate the z-score for the largest piece of Nitrate data - show your calculations using the formula and see textbook page 113 – 114 to explain why x = 22 ppm is or is not an unusual value.

7. From the Data Analysis table, what is the numerical skewness of the data? From the textbook page 56, what does that skewness value mean?

8. The histogram you made in Lab 2 on Lost Creek Nitrate data was made from the same data used for this lab, explain why the skewness value from question 7 is demonstrated in that histogram. Include how the histogram shows frequencies of lower levels of Nitrates compared to frequencies of higher levels of Nitrates.

123 v 8.5 8.37380952 Mean (in PPM 8.8 Mode (in PPM 8.8 Median (in PPM 8.8 9.8 27.3010046 Variance (in PPM squared) 5.22503633 Std. Deviation (in PPM 4.25 25th Percentile (in PPM 11.15 75th Percentile (in PPM 8.8 Column1 8.8 6.6 10 Mean Standard Error Median Mode Standard Deviation Sample Variance Kurtosis Skewness Range Minimum Maximum Sum Count 8.373809524 0.806240609 8.8 12 13 6.6 15 16 17 18 5.22503633 27.30100465 0.098414047 0.404563749 7.8 8.4 20 21 2.2 23 24 25 26 27 28 29 30 31 32 5.2 3.4 8.8 12.1 16.3 19.8 3.5 0.8 9.8 13.2 11.2 8.8 15.5 351.7 42 1.592E+112 1. Compare the formula values to the Descriptive Statistics table values for me 34 35 36 37 38 39 40 2. Explain the meaning of the 25th and 75th percentiles in the context of this d 3. Find the Interquartile Range and show the math calculations and formula us 4. What is the range of all the data? Show your calculation to show that the Da 5. Calculate the z-score for the smallest piece of Nitrate data show your calcu 6.6 0 12.8 0.3 6. Calculate the z-score for the largest piece of Nitrate data-show your calcula 42 43 0.9 7. From the Data Analysis table, what is the numerical skewness of the data? 45

Explanation / Answer

Sol:

mean=8.37

median=8.8

mode=8.8

sample sie=n=42

Distribution is approxiamtely normal.

Solution2:

25 th percentile=4.25

75th percentile=11.15

Solution3:

Q1=first quartile=4.25

Q3=third quartile=11.15

inexcel type range

IQR=inter quartile range=Q3-Q1

=11.15-4.25

=6.9

IQR=6.9

Solution4:

range=max-min

=22-0

=22

sampledata Mean 8.37381 Standard Error 0.806241 Median 8.8 Mode 8.8 Standard Deviation 5.225036 Sample Variance 27.301 Kurtosis 0.098414 Skewness 0.404564 Range 22 Minimum 0 Maximum 22 Sum 351.7 Count 42