# Tutor profile: Kennetha W.

## Questions

### Subject: SAT

A research assistant randomly selected 75 undergraduate students from the list of all students enrolled in the psychology-degree program at a large university. She asked each of the 75 students, “How many minutes per day do you typically spend reading?” The mean reading time in the sample was 89 minutes, and the margin of error for this estimate was 4.28 minutes. Another research assistant intends to replicate the survey and will attempt to get a smaller margin of error. Which of the following samples will most likely result in a smaller margin of error for the estimated mean time students in the psychology-degree program read per day? A. 40 randomly selected undergraduate psychology-degree program students B. 40 randomly selected undergraduate students from all degree programs at the college C. 300 randomly selected undergraduate psychology-degree program students D. 300 randomly selected undergraduate students from all degree programs at the college

By increasing the sample size while selecting participants from the same population will decrease the margin of error. C is the correct answer.

### Subject: Basic Math

Simplify 4 – 3[4 –2(6 – 3)] ÷ 2

Use PEMDAS to solve Parentheses/ Brackets/ Absolute Value Exponents Multiplication/ Divison ( which ever comes first from left to right) Addition/ Subtraction ( which ever comes first from left to right) 4 – 3[4 –2(6 – 3)] ÷ 2 Start with the inner most parenthesis (6-3=3) 4 – 3[4 – 2(3)] ÷ 2 Next perform the multiplication inside the brackets (2(3)=6). 4 – 3[4 – 6] ÷ 2 Next complete the subtraction within the brackets [4-6]=-2 4 – 3[–2] ÷ 2 Next multiply -3[-2]=6 4 + 6 ÷ 2 Next divide 6/2=3 = 4 + 3 Finally add 4+3=7 = 7

### Subject: Algebra

Solve using elimination method. 1. x+2y+z=4 2. 4y-3z=1 3. 2y+10z=12

First we can choose two equations and eliminate one variable. Let start with eliminating "y" using the following equations 2. 4y-3z=1 3. 2y+10z=12 Multiply equation 3 by (-2) to make the coefficients of “y” opposite and add equations together. We eliminate “y” (Reason: 4y+(-4y)=0) 4y-3z=1 +(-4y)-20z=-24 -23z=-23 Reason: Left side(-3z+-20z=-23z); Right side (1+-24=-23) Divide both sides by -23. So z=1 Replace “z” in any equation with “1”. Equations 2 or 3 are the best choices because each only has one other variable. Let’s choose equation 2. 4y-3(1)=1 4y-3=1 Add 3 to both side. Reason: Left side( -3+3=0); Right side(1+3=4) 4y=4 Divide both sides by 4 y=1 Now replace “z” and “y” in any equation to solve for “x”. Let’s choose equation 1. x+2(1)+(1)=4 x+2+1=4 Combine like terms x+3=4 Subtract 3 from both sides. Reason: Left side(3-3=0); Right Side (4-3=1) x=1 Final answer x=1 y=1 z=1

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