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3 years ago

Which substance is detected by a flame test?

Mathematics

2 answers:

Neko [114]3 years ago

8 0

I believe the correct answer is C: gas

QveST [7]3 years ago

7 0

D. metal
Different metals give the flame different colors, giving it a flame test, would identify the presence of a metal.

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5 times 2/8=

sergejj [24]

Answer:

STEP

Simplify ——

Equation at the end of step

-15 k 5

(((————)+((8•—)•k))-————————-10k)+(12•k2))-5k)-12

(k2) 2 (k3)(k2)

STEP

Equation at the end of step 2

-15 k 5

(((————)+((8•—)•k))-————————-10k)+(22•3k2))-5k)-12

(k2) 2 (k3)(k2)

STEP

Equation at the end of step

-15 k 5

(((————)+((8•—)•k))-——————-10k)+(22•3k2))-5k)-12

(k2) 2 (k3)k2

STEP

Simplify ——

Equation at the end of step

-15 k 5

(((————)+((8•—)•k))-————-10k)+(22•3k2))-5k)-12

(k2) 2 k3k2

STEP

Simplify —

Equation at the end of step

-15 k 5

(((————)+((8•—)•k))-————-10k)+(22•3k2))-5k)-12

(k2) 2 k3k2

STEP

Simplify ——

Equation at the end of step

15 5

(((——)+4k2)-————-10k)+(22•3k2))-5k)-12

k2 k3k2

5 0

3 years ago

Miss Wilson has spent $6 on breakfast using her debit card 5 mornings per week for the past 8 weeks. What is the change in Miss

zvonat [6]

Answer:

Step-by-step explanation:

240

3 0

4 years ago

Read 2 more answers

A clinical trial tests a method designed to increase the probability of conceiving a girl. In the study 400 babies were born, a

Masja [62]

Answer:

(a) 99% confidence interval for the percentage of girls born is [0.804 , 0.896].

(b) Yes, the proportion of girls is significantly different from 0.50.

Step-by-step explanation:

We are given that a clinical trial tests a method designed to increase the probability of conceiving a girl.

In the study 400 babies were born, and 340 of them were girls.

(a) Firstly, the pivotal quantity for 99% confidence interval for the population proportion is given by;

P.Q. = $\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ~ N(0,1)

where, $\hat p$ = sample proportion of girls born = $\frac{340}{400}$ = 0.85

n = sample of babies = 400

p = population percentage of girls born

Here for constructing 99% confidence interval we have used One-sample z proportion statistics.

So, 99% confidence interval for the population proportion, p is ;

P(-2.58 < N(0,1) < 2.58) = 0.99 {As the critical value of z at 0.5% level

of significance are -2.58 & 2.58}

P(-2.58 < $\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ < 2.58) = 0.99

P( $-2.58 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ < ${\hat p-p}$ < $2.58 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ) = 0.99

P( $\hat p-2.58 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ < p < $\hat p+2.58 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ) = 0.99

99% confidence interval for p = [ $\hat p-2.58 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ , $\hat p+2.58 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ]

= [ $0.85-2.58 \times {\sqrt{\frac{0.85(1-0.85)}{400} } }$ , $0.85+2.58 \times {\sqrt{\frac{0.85(1-0.85)}{400} } }$ ]

= [0.804 , 0.896]

Therefore, 99% confidence interval for the percentage of girls born is [0.804 , 0.896].

(b) Let p = population proportion of girls born.

So, Null Hypothesis, $H_0$ : p = 0.50 {means that the proportion of girls is equal to 0.50}

Alternate Hypothesis, $H_A$ : p $\neq$ 0.50 {means that the proportion of girls is significantly different from 0.50}

The test statistics that will be used here is One-sample z proportion test statistics;

T.S. = $\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ~ N(0,1)

where, $\hat p$ = sample proportion of girls born = $\frac{340}{400}$ = 0.85

n = sample of babies = 400

So, the test statistics = $\frac{0.85-0.50}{\sqrt{\frac{0.85(1-0.85)}{400} } }$

= 19.604

Now, at 0.01 significance level, the z table gives critical value of 2.3263 for right tailed test. Since our test statistics is way more than the critical value of z as 19.604 > 2.3263, so we have sufficient evidence to reject our null hypothesis due to which we reject our null hypothesis.

Therefore, we conclude that the proportion of girls is significantly different from 0.50.

8 0

3 years ago

Can one of y’all help me please????

amid [387]

Answer:

1,0

Explanation:

Graphically, where the line crosses the x -axis, is called a zero, or root. Algebraically, a zero is an x value at which the function of x is equal to 0 . Linear functions can have none, one, or infinitely many zeros.

7 0

3 years ago

Adding school fairest 20% of the people are under 16 years old one third of the people remaining are teachers if there are 21 te

dedylja [7]

In the fairest school 20% are below 16 years old
1/3 are teachers which is equals to = 21
Let’s start solving:
=> 1/3 of 100% = ( 100 / 3 = 33.33% )
thus 33.33% = 21
=> 21 x 3 = 63, is the total number of people in the school.
Let’s try solving the number of people below 16 years old
Then there are 20% of it:
=> 63 * .20 = 12.6
Thus, there are around 13 people who are 16 years old younger.

4 0

4 years ago