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EastWind [94]
3 years ago
10

A contest is being held at a school fair for seventh-grade

Mathematics
2 answers:
pshichka [43]3 years ago
6 0

Answer:

3/7

Step-by-step explanation:

ofc theres 70 students all together, the 3 represents 30 eighth-graders and the 7 is the 70 students all together, 3+4=7 blah blah blah :)

DerKrebs [107]3 years ago
4 0
The answer is c.. hope this helps
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9 weeks 2 days = ?<br> days?
AnnyKZ [126]

Answer:

9weeks 2days = (9 × 7) + 2 = 63 +2=65 days

Step-by-step explanation:

5 0
3 years ago
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A bag contains 2 white marbles and 7 purple marbles. Two marbles are drawn at random. One marble is drawn and not replaced. Then
Masja [62]
A.
\frac{7purple}{9total} *  \frac{2white}{8total}  \\  \frac{14}{72}  \\ =0.194
The denominator of the second number goes down one because you aren't replacing the initial marble pulled, making the amount of marbles in the bag go down, but not affecting the white count because you pulled a purple marble.
b.
\frac{2white}{9total} *  \frac{1white}{8total}  \\  \frac{2}{72}  \\ =0.278
The same can be said about the denominator for this problem, but not the numerator. The numerator must go down one number as well, because you already chose one white marble, taking one of the white marbles out of the bag, leaving you with one solitary, white marble.
c.
Chance of selecting two purple marbles:
<u />\frac{7purple}{9total} *  \frac{6purple}{8total}  \\  \frac{42}{72}  \\ =0.583
Chance of selecting two white marbles:
\frac{2white}{9total} * \frac{1white}{8total} \\ \frac{2}{72} \\ =0.278
<u>Chance of selecting two purple</u> vs. <em>Chance of Selecting 2 white:</em>
<u>0.583</u>><em>0.278</em>.
It is more likely to select 2 purple marbles.

Hope this helps!
6 0
3 years ago
Read 2 more answers
Send help pleaseeeeeee
valentina_108 [34]

Answer:

The answer is d 1:2

Step-by-step explanation:

5 0
3 years ago
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Engineers at a large automobile manufacturing company are trying to decide whether to purchase brand A or brand B tires for the
andre [41]

Answer:

s_p =\sqrt{\frac{(12 -1)(5100)^2 +(12-1)(5900)^2}{12 +12 -2}}=5514.526

t=\frac{(37900-39800)-0}{5514.526\sqrt{\frac{1}{12}+\frac{1}{12}}}}=-0.844  

p_v =2*P(t_{22}  

Comparing the p value with a significance level for example \alpha=0.1 we see that p_v>\alpha so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can conclude that the true means are not significantly different.  

Step-by-step explanation:

Data given and notation

\bar X_{A}=37900 represent the mean for A

\bar X_{B}=39800 represent the mean for B

s_{A}=5110 represent the sample standard deviation for A

s_{B}=5900 represent the sample standard deviation for B

n_{A}=12 sample size for the group A  

n_{B}=12 sample size for the group B

\alpha Significance level provided  

t would represent the statistic (variable of interest)  

Concepts and formulas to use  

We need to conduct a hypothesis in order to check if the means are equal or not, the system of  hypothesis would be:  

Null hypothesis:\mu_{A}-\mu_{B}= 0  

Alternative hypothesis:\mu_{A} - \mu_{B}\neq 0  

We don't have the population standard deviation's but we assume that the population deviation is equal for both populations, so we can apply a t test to compare means, and the statistic is given by:  

t=\frac{(\bar X_{A}-\bar X_{B})-\Delta}{s_p\sqrt{\frac{1}{n_{A}}+\frac{1}{n_{B}}}} (1)  

Where s_p represent the standard deviation pooled given by:

s_p =\sqrt{\frac{(n_A -1)s^2_A +(n_B -1)s^2_B}{n_A +n_B -2}}

s_p =\sqrt{\frac{(12 -1)(5100)^2 +(12-1)(5900)^2}{12 +12 -2}}=5514.526

t-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.  

With the info given we can replace in formula (1) like this:  

t=\frac{(37900-39800)-0}{5514.526\sqrt{\frac{1}{12}+\frac{1}{12}}}}=-0.844  

P value  

We need to find first the degrees of freedom given by:

df=n_A +n_{B}-2=12+12-2=22

Since is a two tailed test the p value would be:  

p_v =2*P(t_{22}  

Comparing the p value with a significance level for example \alpha=0.1 we see that p_v>\alpha so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can conclude that the true means are not significantly different.  

6 0
4 years ago
12 +3/2s - 1/2 - 3/4s = 5/4s<br><br> How to solve for s?
rodikova [14]

s=1/23

given equation in term of s is 12+3/2s-1/2-3/4s=5/4s

to solve this first we need to take LCM on left hand side and right hand side                                                                                                                                      we can rewrite given equation as 12/1+3/2s-1/2-3/4s=5/4s                                                    now taking LCM of {1,2s,2,4s,4s} is 4s                                                                                  then the equation becomes                                                                                                              48s/4s+6/4s-2s/4s-3/4s=5/4s

(48s+6-2s-3) /4s=5/4s                                                                                                                      now cancel out denominator of both side                                                                                   we get     48s+6-2s-3=5                                                                                                                      this implies 46s+3=5

                 46s=2

                     s=1/23

Hence the value of s is 1/23

learn more about LCM here brainly.com/question/8463488

#SPJ9

3 0
2 years ago
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