STAT 1350: Elementary Statistics Lab Activity #3 Measurement Name Jache Snyder 1
ID: 3376420 • Letter: S
Question
STAT 1350: Elementary Statistics Lab Activity #3 Measurement Name Jache Snyder 1. The age of a Pine tree was measured five times independently using a new lectronic probe inserted in the tree's trunk. The measured values were 46 years old, 45 years old, 47 years old, 45 years old, and 47 years old. Later this same was cut down and, by counting the growth rings, it was determined that the was really 34 years old. Does a measurement with this new electronic device for measuring the age of trees have a larger problem with bias or with reliability? tree Explain. 2. US News and World report conducts an annual report of top colleges and universities. This report ranks each school based on the resources and reputation of the school. A critic of this ranking noted that the rankings look only at endowments, grants and other resources, but does not look at how successful students who attend the school are after they graduate. Is this critic addressing the bias, reliability or validity of the rankings? Explain. 3. An important factor in determining the value of a home is to examine the size of the lot on which the home is located. A local real estate agent measures the width of a lot by counting the number of squares in the sidewalk across the front of the lot. He then multiplies the number of squares by 3 feet to determine the width of the lot in feet. Another agent offered the following criticisms of this method. Criticism 1: The squares in the sidewalk are often over 3 feet in length. Criticism 2: The squares are rarely the same size. Several lots of the same size could have very different numbers of squares and very different measurements. Criticism 3: To estimate the value of a home the agent should concentrate on the size and features of the home not on the size of the lot. Which of these is about the reliability, which about bias, and which about validity. Explain fully. Crit-5,:'il -Bias because it's not SRS 4. A brand of toothpaste advertises that the new tube holds 8.6 ounces of toothpaste. The old tube held 8 ounces. Find the percent increase.Explanation / Answer
1. It has a greater problem with bias since the electronic probe was systematically giving values that were very high ( around 8 to 9 years older compared to the truth) but they only bounced around by about +/- 2 years with a mean of 42.6 years off of that.
2. The critic is addressing the validity of the rankings because they are not measured correctly as they are not taking into account the success of the student after they graduate which is also an important factor in ranking od schools other than grants, endowments etc. because it tells a lot about the quality of education.
3. Criticism 1: The squares in the sidewalk are often over 3 feet in length.
Validity is the ability of a method or instrument to accurately measure what it intends to or what it is supposed to measure. By measuring the wrong thing the program is engaging in an inaccurate measurement. This criticism is about the fact that squares are often over 3 feet then multiplication with 3 feet will give wrong results.
Criticism 2: The squares are rarely the same size. Several lots of the same size could have very different numbers of squares and very different measurements.
This is also a problem of validity because this criticism is raising the question about the method of measurement which will give wrong as size and number of squares vary and so will the length.
Criticism 3: To estimate the value of a home the agent should concentrate on the size and features of the home, not on the size of the lot.
The absence of outcome data from the subgroup of the measurements means that results will underrepresent details of the house needed by buyer. Results are likely to be biased towards overestimating the cost of the house
4. The percent increase = (0.6/8)*100% = 7.5%
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.