Mathematics, 23.07.2019 15:30, tinyiaihfurlow

The manager of a warehouse would like to know how many errors are made when a product’s serial number is read by a bar-code reader. six samples are collected of the number of scanning errors: 36, 14, 21, 39, 11, and 2 errors, per 1,000 scans each. 1a.] what is the mean and standard deviation for these six samples? 2a.] what number of errors is made by all scans, based on these six samples? just to be sure, the manager has six more samples taken: 33, 45, 34, 17, 1, and 29 errors, per 1,000 scans each 1b.] how do the mean and standard deviation change, based on all 12 samples? 2b.] how reasonable is it to expect that the small sample represents larger samples?

Answers: 1

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answered: liamgreene90

1A) Mean=20.5 SD=176.25
2A) 17

answered: talahtoo2924

1A. 20.5

2A. 14.54

1B. 14.625

2B. quite good reasonable

Step-by-step explanation:

Mean is used to measure central tendency (i.e. representative of data) and standard deviation is use to measure dispersion of data. The formula use to calculate mean and variance is :

$Mean(bar{x}) = \dfrac{Sum of all the observations}{Total number of observation}$

$Standard deviation(\sigma) = \sqrt{\frac{1}{n} \sum_{i=1}^{n}(x_{i}-\bar{x})^2}$

1A. Mean of six sample =

$= \dfrac{Sum of all the observations}{Total number of observation}$

⇒ $\dfrac{36+14+21+39+11+2}{6}$

⇒ Mean = 20.5

Standard deviation of six sample =

$= \sqrt{\frac{1}{6}[ (36-20.5)^2+(14-20.5)^2+(21-20.5)^2+(39-20.5)^2+(11-20.5)^2+(2-20.5)^2}]$

⇒ σ = 14.54

2A. Total number of error = 36 + 14 + 21 + 39 + 11 + 2 = 123

Total number of error made by all scans is 123 error per 6000 scans.

1B. Mean of all 12 samples is:

$= \dfrac{Sum of all the observations}{Total number of observation}$

⇒ $\dfrac{36+14+21+39+11+2+33+45+34+17+1+29}{12}$

⇒ Mean = 23.5

Standard deviation of all 12 samples =

$= \sqrt{\frac{1}{12}[ (36-23.5)^2+(14-23.5)^2+(21-23.5)^2+(39-23.5)^2+(11-23.5)^2+(2-23.5)^2+(33-23.5)^2+(45-23.5)^2+(34-23.5)^2+(17-23.5)^2+(1-23.5)^2+(29-23.5)^2}]$

⇒ σ = 14.625

2B. Taking small sample instead of large sample can be quite risky sometimes as larger sample give us more accurate result than small sample.

But here we can take a small sample because the mean of both the size of the sample is near about.

answered: Guest

the system of inequity is

$y\leq -x+4$

$3y> x$

step-by-step explanation:

from the given graph it is noticed that we have two related lines. one is solid and another is dashed.

if a line passing through two points, then the equation of line is

$y-y_1=\frac{y_2-y_1}{x_2-x_1}(x-x_1)$

the solid line passing through the points (0,4) and (4,0).

$y-4=\frac{0-4}{4-0}(x-0)$

$y=-x+4$

the related equation of solid line is $y=-x+4$ .

similarly, find the related equation of dashed line. the dashed liune passing through the points (0,0) and (3,1).

$y-0=\frac{0-1}{3-0}(x-0)$

$3y=x$

the related equation of dashed line is $3y=x$

from the given graph it is noticed that the point (0,1) lies on the shaded region, therefore the point (0,1) must be satisfied by the related equations.

check the related equations by the point (0,1).

$1=-0+4$

$1=4$

this statement is true if the sign of inequality is < instead of equality. since it is an solid line therefore the sign of inequality will be $\leq$ . the required inequality is

$y\leq -x+4$

similarly, check the second related equation.

$3(1)=0$

it is a dashed line, so this statement is true if the sign of inequality is > . the required inequality is

$3y> x$

15 points write a system of inequalities to represent the shaded portion of the graph

answered: Guest

i can't read the graph

step-by-step explanation:

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