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schepotkina [342]
3 years ago
9

A student performed an experiment to determine the effect of acid rain on plant growth. The student divided 80 seeds of a fast-g

rowing plant species into four groups of 20 seeds each. The four groups of seeds were then planted in soil. After all of the seeds germinated in the same growing conditions, they were watered once a day with simulated rainwater that had different levels of acidity. The acidity of the four different watering solutions was as follows:
neutral water, 0.1%, 1.0%, and 10%. The average height of the plants in each group was measured over a two-week period.

Complete the following items using the information above

a. Identify the independent variable in the experiment.
b. Describe the control in the experiment.
c. Based on the described experiment, state a valid hypothesis for the experiment.
d. The experiment was repeated and each soil had the addition of crushed limestone. Describe how the modification of the study would affect the results.
Mathematics
1 answer:
Marta_Voda [28]3 years ago
6 0

Answer:

a) The independent variable is the variable which is being taken as the source of an observation. It is the variable which is unaffected (changed) by other factors in the experiment

Here the independent variable is the acidity (concentrations) of the watering solutions

b, The control in the experiment is the plant group which are not administered the treatment of the experiment, such that they are kept the same through out to aid in validation of the correlation between the dependent and the independent variables

The control in the experiment are the group of 20 plants that received neutral water

c. A valid hypothesis is that there is no difference in the level of growth of a plant grown in acid rain and one grown with natural water

d. Limestone is composed of calcium carbonate, which is an alkaline that dissolves in water to form a basic solution that neutralizes the effect of the added acid such that it will invalidate the correlation of the level of plant growth with exposure to acid rain

Step-by-step explanation:

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Six added to 3 times a number is equal to 4 less than 5 times the number. What is the number?
harina [27]

Answer:

5

Step-by-step explanation:

Let the number be x.

3x+6=5x-4

3x-5x=-4-6

-2x=-10

2x=10

2x/2=10/2

x=5

The number is 5.

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3 years ago
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A libary has 2000 books. there are 3 times as many non fiction books as fiction books. write and solve a system of equations to
Andru [333]
A: number of nonfiction books 
b: number of fiction books
a+b=2000
a=3b
b=500
a=1500
4 0
3 years ago
The sum of 12 and the product of 9 and a number results in 57
xxTIMURxx [149]
If i read this correctly then the answer would be 
57-12= 45
45/9= 5

The answer is 5
7 0
3 years ago
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According to the empirical rule, if the data form a "bell-shaped" normal distribution, ________ percent of the observations will
jekas [21]
According to empirical rule, the area under the normal distribution or "bell-shaped curve", when plotted as a function of the z-parameter can be defined in terms of percentages.
The z-parameter (or z-score) is defined as
z= \frac{x- \mu }{ \sigma }
where
x =  value of random variable,
μ = the mean,
σ = standard deviation,

The total area under the curve = 1.
The curve below shows that within 2 standard deviations from the mean, the total area under the curve is 95%  of the total area.



Answer: 95%

5 0
3 years ago
1. A waste management service attempts to design routes so that each of their trucks pick-up on average four tons of garbage or
Galina-37 [17]

Answer:

We conclude that garbage collector's average picking is more than four tons of garbage per day.

Step-by-step explanation:

We are given the following information n the question:

First, we design the null and the alternate hypothesis

H_{0}: \mu \leq 4\text{ tons}\\H_A: \mu > 4\text{ tons}

Significance level = 5% = 0.05

P-value = 0.04

  • The p-value is the probability of obtaining the observed results of a test, assuming that the null hypothesis is correct.
  • P values evaluate how well the sample data support that the null hypothesis is true.
  • P-value is a measure or indicator that helps us to know that whether the sample belongs to the population or not.
  • Null hypothesis states that the sample belongs to the population.
  • A high p-values states that the null hypothesis is true ad the sample belongs to the population.ll.
  • A low p-value suggests that sample provides enough evidence that you the null hypothesis is not true and the sample does not belong to the population.
  • We compare p-value to significance level to obtain our result.

Here,

p-value = 0.04 < Significance level = 0.05

Since the p-value is lower than the significance level, we fail to accept the null hypothesis and reject it. That is there were enough evidence to support the fact that sample does not belong to the population and we conclude that garbage collector's average picking is more than four tons of garbage per day.

6 0
3 years ago
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