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OverLord2011 [107]

3 years ago

13

You are interested in determining which of two brands of light bulbs, brand A and brand B, lasts longer under differing conditio

ns of use. Fifty Bovano lamps are fitted with brand A light bulbs and 50 Bulbrite lamps are fitted with brand B light bulbs. Each light bulb is left on for 20,000 hours straight. Light bulb life is then measured for each bulb, and the average light bulb life for the two brands is compared. What is wrong with this experimental design?
Nothing is wrong with this design.
The type of lamp is a confounding variable.
Not enough light bulbs of each type are used in the study.
The experiment should have been conducted on more than two brands of lamps.

2 answers:

bulgar [2K]3 years ago

7 0

Answer:

The type of lamp is a confounding variable.

Step-by-step explanation:

to test the average life of the bulbs the same lamps should be used

Fofino [41]3 years ago

5 0

Answer:

The answer would be A. 1 1/5

Hope this helps!!!

Step-by-step explanation:

You might be interested in

Factor Quadratics

klasskru [66]

Answer:

(x−3)(x−8)

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers

Naomi has earned $81 mowing lawns the past two days. She worked 2 1/2 hours yesterday and 4 1/4 hours today. If Naomi is paid th

Anettt [7]

Answer:

Twelve dollars per hour

Step-by-step explanation:

Add 2 1/2 and 4 1/4 together to get 6 3/4. Put it into decimal form (6.75), and divide. 81 ÷ 6.75 = 12.

3 0

3 years ago

(−m <br> 2<br> +6)+(−4m <br> 2<br> +7m+2)

dmitriy555 [2]

Following are calculation to the given eqution:

Given:

$\bold{(-m^2+6)+(-4m^2+7m+2)}$

To find:

Solve the equation.

Solution:

$\to \bold{(-m^2+6)+(-4m^2+7m+2)}\\\\\to \bold{-m^2+6-4m^2+7m+2}\\\\\to \bold{-5m^2+7m+8}\\\\\to \bold{-1(5m^2-7m-8)}\\\\$

Therefore, the final solution is " $-1(5 m^2-7m-8)$ ".

Learn more:

brainly.com/question/12685776

7 0

2 years ago

Bogdan [553]

Answer:

option 2, 3, and 5

Step-by-step explanation:

yuh

7 0

3 years ago

The system of equations may have a unique solution, an infinite number of solutions, or no solution. Use matrices to find the ge

Leno4ka [110]

Answer:

Infinite number of solutions.

Step-by-step explanation:

We are given system of equations

$5x+4y+5z=-1$

$x+y+2z=1$

$2x+y-z=-3$

Firs we find determinant of system of equations

Let a matrix A= $\left[\begin{array}{ccc}5&4&5\\1&1&2\\2&1&-1\end{array}\right]$ and B= $\left[\begin{array}{ccc}-1\\1\\-3\end{array}\right]$

$\mid A\mid=\begin{vmatrix}5&4&5\\1&1&2\\2&1&-1\end{vmatrix}$

$\mid A\mid=5(-1-2)-4(-1-4)+5(1-2)=-15+20-5=0$

Determinant of given system of equation is zero therefore, the general solution of system of equation is many solution or no solution.

We are finding rank of matrix

Apply $R_1\rightarrow R_1-4R_2$ and $R_3\rightarrow R_3-2R_2$

$\left[\begin{array}{ccc}1&0&1\\1&1&2\\0&-1&-3\end{array}\right]$ : $\left[\begin{array}{ccc}-5\\1\\-5\end{array}\right]$

Apply $R_2\rightarrow R_2-R_1$

$\left[\begin{array}{ccc}1&0&1\\0&1&1\\0&-1&-3\end{array}\right]$ : $\left[\begin{array}{ccc}-5\\6\\-5\end{array}\right]$

Apply $R_3\rightarrow R_3+R_2$

$\left[\begin{array}{ccc}1&0&1\\0&1&1\\0&0&-2\end{array}\right]$ : $\left[\begin{array}{ccc}-5\\6\\1\end{array}\right]$

Apply $R_3\rightarrow- \frac{1}{2}$ and $R_2\rightarrow R_2-R_3$

$\left[\begin{array}{ccc}1&0&1\\0&1&0\\0&0&1\end{array}\right]$ : $\left[\begin{array}{ccc}-5\\\frac{13}{2}\\-\frac{1}{2}\end{array}\right]$

Apply $R_1\rightarrow R_1-R_3$

$\left[\begin{array}{ccc}1&0&0\\0&1&0\\0&0&1\end{array}\right]$ : $\left[\begin{array}{ccc}-\frac{9}{2}\\\frac{13}{2}\\-\frac{1}{2}\end{array}\right]$

Rank of matrix A and B are equal.Therefore, matrix A has infinite number of solutions.

Therefore, rank of matrix is equal to rank of B.

4 0

3 years ago