Then c=mb=mna(since b=na).since mn is an integer, so this implies that a|c

asked 2021-02-01

asked 2021-06-13

Let [A[A b]b] be the augmented matrix of a system of linear equations. Prove that if its reduced row echelon form is [R[R c]c], then R is the reduced row echelon form of A.

asked 2021-02-25

Let a, b, c, \(\displaystyle{m}\in{Z}\) such that m > 1. If \(\displaystyle{a}{c}\equiv{b}{c}{\left(\mod\right)},{t}{h}{e}{n}\ {a}\equiv{b}{\left(\mod{m}\right)}\)

asked 2021-04-06

Prove directly from the definition of congruence modulo n that if a,c, and n are integers,n >1, and \(\displaystyle{a}\equiv{c}{\left({b}\text{mod}{n}\right)}\), then \(\displaystyle{a}^{{{3}}}\equiv{c}^{{{3}}}{\left({b}\text{mod}{n}\right)}\).

asked 2021-01-04

asked 2021-03-18

asked 2020-11-06

(ii)Prove that the converse of(i) is also true.That is to say, if there exists a constant c such that \(v_1 = c v_2\ or\ v_2 = c v_1\), 1. then\({v_1,v_2}\)is linearly dependent.

asked 2021-02-23

Interpreting z-scores: Complete the following statements using your knowledge about z-scores.

a. If the data is weight, the z-score for someone who is overweight would be

-positive

-negative

-zero

b. If the data is IQ test scores, an individual with a negative z-score would have a

-high IQ

-low IQ

-average IQ

c. If the data is time spent watching TV, an individual with a z-score of zero would

-watch very little TV

-watch a lot of TV

-watch the average amount of TV

d. If the data is annual salary in the U.S and the population is all legally employed people in the U.S., the z-scores of people who make minimum wage would be

-positive

-negative

-zero

a. If the data is weight, the z-score for someone who is overweight would be

-positive

-negative

-zero

b. If the data is IQ test scores, an individual with a negative z-score would have a

-high IQ

-low IQ

-average IQ

c. If the data is time spent watching TV, an individual with a z-score of zero would

-watch very little TV

-watch a lot of TV

-watch the average amount of TV

d. If the data is annual salary in the U.S and the population is all legally employed people in the U.S., the z-scores of people who make minimum wage would be

-positive

-negative

-zero

asked 2021-01-17

A new thermostat has been engineered for the frozen food cases in large supermarkets. Both the old and new thermostats hold temperatures at an average of \(25^{\circ}F\). However, it is hoped that the new thermostat might be more dependable in the sense that it will hold temperatures closer to \(25^{\circ}F\). One frozen food case was equipped with the new thermostat, and a random sample of 21 temperature readings gave a sample variance of 5.1. Another similar frozen food case was equipped with the old thermostat, and a random sample of 19 temperature readings gave a sample variance of 12.8. Test the claim that the population variance of the old thermostat temperature readings is larger than that for the new thermostat. Use a \(5\%\) level of significance. How could your test conclusion relate to the question regarding the dependability of the temperature readings? (Let population 1 refer to data from the old thermostat.)

(a) What is the level of significance?

State the null and alternate hypotheses.

\(H0:?_{1}^{2}=?_{2}^{2},H1:?_{1}^{2}>?_{2}^{2}H0:?_{1}^{2}=?_{2}^{2},H1:?_{1}^{2}\neq?_{2}^{2}H0:?_{1}^{2}=?_{2}^{2},H1:?_{1}^{2}?_{2}^{2},H1:?_{1}^{2}=?_{2}^{2}\)

(b) Find the value of the sample F statistic. (Round your answer to two decimal places.)

What are the degrees of freedom?

\(df_{N} = ?\)

\(df_{D} = ?\)

What assumptions are you making about the original distribution?

The populations follow independent normal distributions. We have random samples from each population.The populations follow dependent normal distributions. We have random samples from each population.The populations follow independent normal distributions.The populations follow independent chi-square distributions. We have random samples from each population.

(c) Find or estimate the P-value of the sample test statistic. (Round your answer to four decimal places.)

(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis?

At the ? = 0.05 level, we fail to reject the null hypothesis and conclude the data are not statistically significant.At the ? = 0.05 level, we fail to reject the null hypothesis and conclude the data are statistically significant. At the ? = 0.05 level, we reject the null hypothesis and conclude the data are not statistically significant.At the ? = 0.05 level, we reject the null hypothesis and conclude the data are statistically significant.

(e) Interpret your conclusion in the context of the application.

Reject the null hypothesis, there is sufficient evidence that the population variance is larger in the old thermostat temperature readings.Fail to reject the null hypothesis, there is sufficient evidence that the population variance is larger in the old thermostat temperature readings. Fail to reject the null hypothesis, there is insufficient evidence that the population variance is larger in the old thermostat temperature readings.Reject the null hypothesis, there is insufficient evidence that the population variance is larger in the old thermostat temperature readings.

(a) What is the level of significance?

State the null and alternate hypotheses.

\(H0:?_{1}^{2}=?_{2}^{2},H1:?_{1}^{2}>?_{2}^{2}H0:?_{1}^{2}=?_{2}^{2},H1:?_{1}^{2}\neq?_{2}^{2}H0:?_{1}^{2}=?_{2}^{2},H1:?_{1}^{2}?_{2}^{2},H1:?_{1}^{2}=?_{2}^{2}\)

(b) Find the value of the sample F statistic. (Round your answer to two decimal places.)

What are the degrees of freedom?

\(df_{N} = ?\)

\(df_{D} = ?\)

What assumptions are you making about the original distribution?

The populations follow independent normal distributions. We have random samples from each population.The populations follow dependent normal distributions. We have random samples from each population.The populations follow independent normal distributions.The populations follow independent chi-square distributions. We have random samples from each population.

(c) Find or estimate the P-value of the sample test statistic. (Round your answer to four decimal places.)

(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis?

At the ? = 0.05 level, we fail to reject the null hypothesis and conclude the data are not statistically significant.At the ? = 0.05 level, we fail to reject the null hypothesis and conclude the data are statistically significant. At the ? = 0.05 level, we reject the null hypothesis and conclude the data are not statistically significant.At the ? = 0.05 level, we reject the null hypothesis and conclude the data are statistically significant.

(e) Interpret your conclusion in the context of the application.

Reject the null hypothesis, there is sufficient evidence that the population variance is larger in the old thermostat temperature readings.Fail to reject the null hypothesis, there is sufficient evidence that the population variance is larger in the old thermostat temperature readings. Fail to reject the null hypothesis, there is insufficient evidence that the population variance is larger in the old thermostat temperature readings.Reject the null hypothesis, there is insufficient evidence that the population variance is larger in the old thermostat temperature readings.

asked 2021-02-14

A ferry boat transports tourists among three islands. It sails from the first island to the second island, 4.42 km away, in a direction 37.0° north of east. It then sails from the second island to the third island in a direction 80.5° west of north. Finally it returns to the first island, sailing in a direction 28.0° east of south. (a) Calculate the distance between the second and third islands. km (b) Calculate the distance between the first and third islands.