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Leona [35]
1 year ago
5

What is the sum of these numbers? +7+(-4)=

Mathematics
1 answer:
nevsk [136]1 year ago
3 0

Answer:

3

Step-by-step explanation:

Since + × - = -

The - sign will change

+7 - 4 = 3

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There are 40 pupils in a class. 75% of them are present. How may are present? How many are absent?
Aleonysh [2.5K]

Answer:

30 are present 10 are absent

Step-by-step explanation:

75%=3/4

so 3/4 of them are absent

3/4(40)=30

and 40-30=10 are absent

8 0
2 years ago
Please add the numbers to the graph and show the work on a paper and post it please if you do not know the answer do not comment
tresset_1 [31]

Answer:

merry crisis

Step-by-step explanation:

8 0
3 years ago
A medical researcher wondered if there is a significant difference between the mean birth weight of boy and girl babies. Random
Yuliya22 [10]

Answer:

b) independent samples t-test

t=\frac{(5.92 -5.74)-(0)}{\sqrt{\frac{1.88^2}{5}}+\frac{1.81^2}{5}}=0.154  

p_v =2*P(t_{8}>0.154) =0.881  

So with the p value obtained and using the significance level given \alpha=0.05 we have p_v>\alpha so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the mean of the group 1 (boys) is NOT significantly different than the mean for the group 2 (Girls).  

Step-by-step explanation:

The system of hypothesis on this case are:  

Null hypothesis: \mu_1 = \mu_2  

Alternative hypothesis: \mu_1 \neq \mu_2  

Or equivalently:  

Null hypothesis: \mu_1 - \mu_2 = 0  

Alternative hypothesis: \mu_1 -\mu_2\neq 0  

Our notation on this case :  

n_1 =5 represent the sample size for group 1  

n_2 =5 represent the sample size for group 2  

We can calculate the mean and deviation for eaach group with the following formulas:

\bar X= \frac{\sum_{i=1}^n X_i}{n}

s = \sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}

\bar X_1 =5.92 represent the sample mean for the group 1  

\bar X_2 =5.74 represent the sample mean for the group 2  

s_1=1.88 represent the sample standard deviation for group 1  

s_2=1.81 represent the sample standard deviation for group 2  

If we see the alternative hypothesis we see that we are conducting a bilateral test and with independnet samples t test.

b) independent samples t-test

The statistic is given by this formula:  

t=\frac{(\bar X_1 -\bar X_2)-(\mu_{1}-\mu_2)}{\sqrt{\frac{s^2_1}{n_1}}+\frac{S^2_2}{n_2}}  

And now we can calculate the statistic:  

t=\frac{(5.92 -5.74)-(0)}{\sqrt{\frac{1.88^2}{5}}+\frac{1.81^2}{5}}=0.154  

The degrees of freedom are given by:  

df=5+5-2=8

And now we can calculate the p value using the altenative hypothesis:  

p_v =2*P(t_{8}>0.154) =0.881  

So with the p value obtained and using the significance level given \alpha=0.05 we have p_v>\alpha so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the mean of the group 1 (boys) is NOT significantly different than the mean for the group 2 (Girls).  

7 0
3 years ago
Need help on this anything will help as this point tbh?!?!
Assoli18 [71]

Answer:

Radius = 1 in

then the volume of bubble = 4/3 π r^3

= (4/3 × 22/7 × 1) in^3 = 88/21 in^3

Hope it helps

5 0
2 years ago
12 tickets sold for every 4 tickets not sold if 704 were not sold how many tickets were sold
horsena [70]

there would be 14 tickets

4 0
3 years ago
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