LSP 121

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LSP 121

• final exam review

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1) The Pacific tectonic plate moves at a rate of
4/year. What is this in miles per hour?

• 4 in x yr x da x ft x mi
  yr 365 da 24 hr 12 in 5280 ft
• 4 miles 365 x 24 x
  12 x 5280 hr
• 7.2 x 10-9 mi/hr

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2) Convert 1 0 1 1 0 1 0 0 2 from binary to
decimal SHOW WORK

1 0 1 1 0 1 0 0
Write powers of 2, right to left, then sum the
numbers above the 1s
128 64 32 16 8 4 2 1
1 0 1 1 0 1 0 0
128 32 16 4 180 (ans)
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3) Convert 3 8 F 216 from hex to decimal SHOW
WORK

3 8 F 2
Put powers of 16 (right to left) above the
cells.160 1, 161 16, 163 256, 164 4096
Multiply lower number times upper number.
Remember A 10, B 11, C 12, F 15 Add
these four products.
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Converting base 16 to decimal
4096 256 16 1

DEC HEX
DEC HEX
DEC HEX
DEC HEX
0 0
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
10 A
11 B
12 C
13 D
14 E
15 F
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4) What is the probability of NOT rolling a
double-6 with two dice?

• There is 1/36 chance of rolling two sixes
• P(not A) 1 P(A)
• 1 1/36 35/36 or .972

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5) Suppose event A has a 0.98 probability of
occurring and event B has a 0.94 probability of
occurring. Compute the ODDS for event A and the
ODDS for event B

• odds are calculated by usingP(A) / P(not A)
• Odds for event A 0.98 / 0.02 49/1 or 49 to 1
• Odds for event B 0.94 / 0.06 15.67/1 or 15.7
  to 1

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6) What is the probability of the next 5 births
at a hospital all being girls?

• Probability of multiple events is calculated by
  the product of the probabilities
• ½ ½ ½ ½ ½ 1/32 or .031
• You can also show (1/2)5 1/32

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7) If Peoria, IL is hit by a tornado about every
30 years, what is the probability that Peoria
will be hit by a tornado this year?

• simply 1/30
• What is the probability that Peoria will be hit
  by tornados in three consecutive years?
• 1/30 1/30 1/30 1/27,000
• at least once in the next 30 years?
• 1 (not A)30 1 (29/30)30
• ANS .64 .6383

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8) see problem

• For CA227,381 deaths / 30,000,000 ppl
  0.00758multiply this by 1000 7.58 deaths /
  1000
• For AK2,911 deaths / 550,000 ppl
  0.005293multiply this by 1000 5.29 deaths /
  1000
• Dont forget to answer the questions included
  with this problem

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9a) How many different license plates are
possible if you have plates with 3 letters
followed by 3 numerals?
Use 6 boxes and enter the possible number of
values for each part of the license plate
26 26 26 10 10 10
Multiply these numbers and you get 17,576,000
possible plates
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9b) How many different 10-note tunes can be
created from the notes A, B, C, D, E, F and G?

• Use 10 boxes and the possible notes per box

7 7 7 7 7 7 7 7 7 7
Multiply or calculate 710 and you
get 282,475,249 possible tunes
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problem 10

• Lottery ticket costs 2, so you start with-2
  1, then add the possible wins
• 21/50 1,0001/2,000 2,0001/4,000
  20,0001/40,000
• -2 .04 .50 .50 .50
• expected value - 0.96
• you lose

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Problems 11, 12

• If you get a problem like 10 or 11 on the exam
  you will be given the Excel formula required to
  do the calculations
• remember, in Excel log(x,b) means the log
  of x, base b

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11) use Excel to work this out, see below

• Note signal .4 and noise .0002
• in Excel set up 2 columns
• 1000 to 10,000 increments of 500, and
• cell log ((1 .4/.0002),2), looks like
• with 1000 in cell A1, 1500 in cell A2

indicates base 2
Frequency (Hz) Bits per second
1000 A1log((1.4/.0002),2)
1500 A2log((1.4/.0002),2)
2000 A2log((1.4/.0002),2)
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12) use Excel to work this out, similar to 11),
see below

• Note W frequency and M 8
• in Excel set up 2 columns
• 1000 to 10,000 increments of 500, and
• 2 cell log (8,2), looks like
• with 1000 in cell A1, 1500 in cell A2

Bandwidth Data rate in Hertz
1000 2A1log(8,2)
1500 2A2log(8,2)
2000 2A3log(8,2)
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13. Programming question

• keep track of the value of i and j and work
  through the nested loops
• total number of outputs 40
• start with this

i j OUTPUT.SCREEN i,j
1 1 1
1 2 2
1 3 1 3
2 1 1
2 2 2 2 etc
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another method..

• You can enter the following as code in VBA for
  Excel
• FOR i 1 TO 4FOR j 1 TO 3 MsgBox i
  jNext jNext i
• Then Run the macro in Excel
• Notice there will be 4 x 3 outputs (12)

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Standard HTML

• lthtmlgt
• ltheadgtlttitlegt lt/titlegtlt/headgt
• ltbodygt
• .. contents of body
• lt/bodygt
• lt/htmlgt
• DO NOT REPEAT html, head, or body

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Insert javascript in webpage

• The following is a trigger in HTML code that
  signals some javascript (what is in italics is
  explanatory and not actual code
• ltscript type text/javascriptgt
• java script code follows
• lt/scriptgt is used to end the javascript part

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Macros and VBA

• relates to question 14, 15
• macro is best used when
• you have to repeat a complex operation
• a single operation involves many steps
• for simulations
• given CELLS(2,3) CELLS(2,3)4
• this will add 4 to contents of cell row 2, column
  3 that sum is put in cell(2,3)

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What is an algorithm, 16

• An orderly sequence of steps that can be followed
  to produce a desired result
• Algorithms are used in
• manufacturing
• testing
• computer programming languages
• making decisions

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Q 17, risk analysis

• First note what is GIVEN
• expected probability of cancer 1/6000 0.017
• reliability of test 75
• number of people with tumors 10,000
• To find
• percentage that will receive a true positive
• percentage that will receive a false negative

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Use the 5 steps to complete the matrix

• Beginning of matrix

Tumor is cancerous Tumor is benign Totals
Positive 75 of 1.67 1.25true positives
Negative false negatives 75 of 9998.33 7498.75
Total 1/6000 10000 1.67 9998.33 10,000
Find the 4 missing values (the true positives and
true negatives have been filled in).
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Now find

• Percentage of true positives
• 1.25 divided by total positives (express this as
  a percentage)
• Percentage of false negatives
• false negatives are negative test results which
  in fact are cancerous (not calculated yet)
• divide this by the total number of negatives (far
  right column in negative row)