Basic Statistic
MTH 160: Minitab #1
Minitab is very similar to an excel spread sheet. When you enter data, you will always be entering the data going down the columns NOT across.Please copy all your graphs to a word documentand in the same document,answer the questions in complete sentences. (5 points for complete sentences and neatness)
To copy a graph to a word document, click on the graph, go to file, copy graph, go to the word document, click on where you want to past your graph and click on paste. If you click on your graph, after you paste it, you can make it smaller.
There is a folder “Minitab videos” if you need help creating any of the graphs throughout the course.
1. The following duration times (seconds) were randomly chosen during a three month period, oferuptions of the Old Faithful geyser in Yellowstone National Park.
275 230 253 234 234 235 237 240 243 245 245 270
270 220 251 252 254 255 258 279 270 276 279 270
280 234 245 235 256 267 220
1a. Using Minitab, create a box and whiskers.
Minitab instructions for creating a box-and-whisker display using Minitab.(3 points)
Enter the above data (eruption times of Old Faithful in C1 going down). Please make sure you label C1.
Choose: Graph > Boxplot > one Y, Simple > ok
Enter: Graph Variables: double click C1
Select: Labels > Titles/ Footnotes > ok
1b. Looking at your box and whiskers display discuss your findings by answering the following questions:
a. Write down the numbers that represent the 5 – number summary. (2 points)
b. Determine what your IQRis and explain what this means in terms of your data. (3 points)
c. How many of the eruptions were between: (4 points)
1. the first and second quartile? (looking for a number)
2. the first and fourth quartile? (looking for a number)
3. What quartile would the data value 245 be in?
4. What quartile would the data value 280 be in?
d. Determine the range and midrange for your data. (3 points)
e.Looking at your boxplot, if we were to create a histogram would the shape be skewed to the left, skewed to the right, or a normal distribution? Please give a reason for your answer. (4 points)
2. The following data that was randomly chosen, are the ages (years) of actresses at the time they won Oscars for the category of “Best Actresses”.
29 37 28 63 62 26 31 27 27 28 30 33 45 42 29 33 38 34 32 34 42 29 41
29 63 65 39 41 28 40 61
2a. Using Minitab, find the following descriptive statistics: (5 points)
1. the mean.
2. the median.
3. the mode.
4. the standard deviation.
5. First quartile
6 Third quartile
7. The minimum
8. The maximum
Minitab instructions for displaying the above descriptive statistics.
Choose: Stat > Basic Statistics > Display Descriptive Statistics
Enter : Variables C1 > click on statistics > click on the above items> ok
2B. The “range rule of thumb”, states that for many data sets, the vast majority (95%) of sample values lie within 2 standard deviations of the mean. To find the minimum “usual value” you take the mean and subtract 2x the standard deviation. To find the maximum “usual value” you take the mean and add 2 x the standard deviation. ( -2= z score = 2) For the data above determine the range of usual values for ages of actresses winning an Oscar. Looking for the lower and upper boundaries for usual lues.v(4 points)
2c. Using the descriptive statistics you found in 2A, determine the value of the mid-quartile and find the mid-range for this data. (3 points)
2d. Using Minitab create a boxplot. (3 points)
2e. Looking at your boxplot, if we were to create a histogram would the shape be skewed to the left, skewed to the right, or a normal distribution? Please give a reason for your answer. (4 points)
3. The speeds of 55 cars were measured by a radar device on a city street.:
27 23 22 38 43 24 35 26 28 18 20 25
23 22 52 31 30 41 45 29 27 43 29 28 27 25 29 28 24 37 28 29 18 26 33 25 27 25 34 32 36 22 32 33 21 23 24 18 48 23 16 38 26 21 23
Using Minitab, construct a histogram for the same data:
Minitab instructions for constructing a histogram. (5 points)
Enter the above data in C1 going down. Please make sure you label C1.
Then graph > histogram>simple>ok
In the graph variables box click it on, then double click on C1.
Choose labels > titles > and footnotes> Put in your title and your name. <ok
To adjust your histogram: double click anywhere on the bars of the histogram.
Select: binning
Under interval definition, go down to midpoint/cutpoint positions and click it on.
Enter 15 space 21 space ok ok
3a. Describe the shape of your histogram. (3 points)
3b. Determine whether the mean or median would have a higher value and give a reason for your answer.Do not use Minitab to find those values. I want to know just by looking at the histogram what your answer would be.(6 points).
3c. If the speed limit for this city street is 30 miles per hour, should the police department have a police officer stationed on that street to catch speeders? Give a reason for your answer. (5 points)
3d. Using Minitab, find the mean, standard deviation, the minimum, and the maximum. (3 points)
3e. Using the results from 3d determine the range of usual values. (3 points)
4. Twentysalaries,randomly chosen from the thirty people employed at Company XYZ, are recorded below.
$27000, $29500, $32000, $29000, $27500, $26,000, $34000, $40000, $39000, $42000
$31000, $37000, $43000, $44000, $42000, $50000, $49000, $48000, $49000, $48000
4a. Using Minitab determine the mean and standard deviation. (2 points)
4b. Using what you found in 4a, determine the range of usual values (salaries) one would expect to find from this company. (4 points)
4c. Create a box plot for this data. (2 points)
4d.Looking at your boxplot, if we were to create a histogram would the shape be skewed to the left, skewed to the right, or a normal distribution? Please give a reason for your answer. (4 points)
5. How do you spend your day? Think about an average 24 hour day. Then using Minitab, please construct a circle graph (pie chart) showing percentages and frequencies AND a bar graph. (7 points)
How many hours do you:
a) sleep
b) do homework
c) run errands
d) clean
e) work
f) eat
g) relax
h) go to school
i) other
Minitab instructions for creating a pie chart or circle graph.
In C1 enter the categories, sleep, do homework etc. Please label this column.
In C2 enter your frequency (number of hours). Please label this column.
Graph > Pie Chart> chart values from a table > in the categorical variable box, highlight the name that is in C1, double click > in the summary variable double click on what you have in C2 > labels, put in your title and under footnotes put in your name>Slice labels, click on frequency percent> ok>ok.
Minitab instructions for creating a bar graph.
Put the category names in C1 and the frequencies in C2
Graph> bar chart> bars represent values from a table > simple>OK> graph variable box (double click on c2) > Categorical variable double click C1> Labels , your title and name> ok> ok
a. Bar graphs and pie charts are used for qualitative data. Write down two reasons a person might choose a pie chart over a bar graph AND two reasons a person might choose a bar graph over a pie chart. (10 points)
b. Looking at your pie chart, what do you spend the most time doing each day and what proportion of your day does this take up? (3 points)
