Piv txwv ntawm Cov Lus Nug Sib Tham Txog Feem Pua ntawm Cov Ntaub Ntawv Pab Pawg
Cov feem pua yog ib qho kev ntsuas ntawm qhov chaw hauv cov ntaub ntawv suav lej siv los nkag siab txog kev faib tawm ntawm cov ntaub ntawv. Hauv tsab xov xwm no, peb yuav tham txog ntau yam kom paub meej txog yuav ua li cas txiav txim siab txog feem pua rau cov ntaub ntawv uas tau muab faib ua pawg. Peb yuav suav nrog ntau qhov teeb meem piv txwv thiab lawv cov lus piav qhia kom meej txog lub tswv yim no. Cia peb pib nrog kev nkag siab yooj yim txog feem pua thiab tom qab ntawd mus rau cov piv txwv thiab lawv cov lus piav qhia.
Nkag Siab Txog Feem Pua
Ib feem pua yog ib qho nqi uas faib cov ntaub ntawv ua 100 feem sib npaug. Qhov ntawd yog, nth feem pua yog tus nqi hauv qab uas n% ntawm cov ntaub ntawv hauv kev faib tawm poob. Piv txwv li, yog tias cov ntaub ntawv muaj 25th feem pua (P25), nws txhais tau tias 25% ntawm cov ntaub ntawv poob qis dua tus nqi ntawd.
Hauv cov ntaub ntawv uas muab faib ua pawg, peb feem ntau siv cov lus qhia faib zaus los teeb tsa cov ntaub ntawv thiab tom qab ntawd txiav txim siab txog feem pua uas cuam tshuam. Cov lus qhia no nthuav qhia cov ntaub ntawv hauv cov chav kawm tshwj xeeb, uas ua rau peb nkag siab txog kev faib cov ntaub ntawv kom ntxaws ntxiv.
Cov Qauv Feem Pua Hauv Cov Ntaub Ntawv Pab Pawg
Cov qauv dav dav rau kev txiav txim siab nth feem pua (Pn) hauv cov ntaub ntawv pawg yog raws li nram no:
\[
P_n = L + \left( \frac{nN – \sum f_{\text{before}}}{f_{k}} \right) \times c
\]
Qhov twg:
- \(P_n\) yog nth feem pua.
- \(L\) yog ntug qis dua ntawm qhov sib nrug ntawm cov chav kawm feem pua.
- \(n\) yog qhov feem pua uas xav tau (piv txwv li, rau P25, n = 25).
- \(N\) yog tag nrho cov zaus sib sau ua ke.
- \(\sum f_{\text{before}}\) yog qhov zaus sib sau ua ntej lub sijhawm kawm feem pua.
- \(f_{k}\) yog qhov zaus ntawm qhov feem pua ntawm chav kawm.
- \(c\) yog qhov ntev ntawm lub sijhawm kawm.
Piv txwv txog teeb meem
Yuav kom nkag siab zoo dua, cia peb saib cov lus nug piv txwv hauv qab no thiab tham txog nws kom ntxaws.
Piv txwv lus nug 1
Hauv kev soj ntsuam, cov ntaub ntawv tau txais txog qhov siab (hauv cm) ntawm 100 tus tub ntxhais kawm theem siab qib 10 raws li nram no:
Lub Sijhawm Kawm | Zaus |
|——————-|———–|
| 150 – 154 | 5 |
| 155 – 159 | 8 |
| 160 – 164 | 12 |
| 165 – 169 | 20 |
| 170 – 174 | 30 |
| 175 – 179 | 15 |
| 180 – 184 | 10 |
Xam qhov feem pua ntawm 40th (P40) ntawm cov ntaub ntawv.
Cov Kauj Ruam Yuav Ua Li Cas Thiaj Daws Tau
1. Txheeb xyuas qhov zaus sib sau ua ke rau txhua chav kawm:
| Lub Sijhawm Kawm | Zaus | Zaus Sib Sau Ua Ke |
|——————-|————–|—————————|
| 150 – 154 | 5 | 5 |
| 155 – 159 | 8 | 13 |
| 160 – 164 | 12 | 25 |
| 165 – 169 | 20 | 45 |
| 170 – 174 | 30 | 75 |
| 175 – 179 | 15 | 90 |
| 180 – 184 | 10 | 100 |
2. Txheeb xyuas qhov sib txawv ntawm cov chav kawm feem pua (P40):
Vim peb tab tom nrhiav P40, peb xav tau 40% ntawm 100 tus tub ntxhais kawm, uas yog 40 tus tub ntxhais kawm. Saib ntawm lub rooj sib piv zaus, peb pom tias 40 tus tub ntxhais kawm pw hauv chav kawm nruab nrab 165 - 169 cm vim 45 yog thawj qhov zaus sib piv uas tshaj 40.
3. Nrhiav cov nqi tsim nyog hauv cov mis:
– \(L = 164.5\)
– \(nN = 40\)
– \(\sum f_{\text{before}} = 25\)
– \(f_k = 20\)
– \(c = 5\)
4. Sau cov nqi rau hauv tus qauv:
\[
P_{40} = 164.5 + \sab laug ( \frac{40 – 25}{20} \sab xis) \times 5
\]
\[
P_{40} = 164.5 + \sab laug (\frac{15}{20} \sab xis) \times 5
\]
\[
P_{40} = 164.5 + 0.75 \times 5
\]
\[
P_{40} = 164.5 + 3.75
\]
\[
P_{40} = 168.25
\]
Yog li, qhov feem pua 40 (P40) ntawm cov ntaub ntawv yog 168.25 cm.
Piv txwv lus nug 2
Xav tias muaj cov ntaub ntawv qhab nia xeem lej los ntawm ib pawg ntawm 200 tus tub ntxhais kawm:
Lub Sijhawm Kawm | Zaus |
|——————-|———–|
| 40 – 44 | 10 |
| 45 – 49 | 18 |
| 50 – 54 | 32 |
| 55 – 59 | 45 |
| 60 – 64 | 50 |
| 65 – 69 | 25 |
| 70 – 74 | 12 |
| 75 – 79 | 8 |
Xam qhov feem pua ntawm 75th (P75) ntawm cov ntaub ntawv.
Cov Kauj Ruam Yuav Ua Li Cas Thiaj Daws Tau
1. Txheeb xyuas qhov zaus sib sau ua ke rau txhua chav kawm:
| Lub Sijhawm Kawm | Zaus | Zaus Sib Sau Ua Ke |
|——————-|————–|—————————|
| 40 – 44 | 10 | 10 |
| 45 – 49 | 18 | 28 |
| 50 – 54 | 32 | 60 |
| 55 – 59 | 45 | 105 |
| 60 – 64 | 50 | 155 |
| 65 – 69 | 25 | 180 |
| 70 – 74 | 12 | 192 |
| 75 – 79 | 8 | 200 |
2. Txheeb xyuas qhov sib txawv ntawm cov chav kawm feem pua (P75):
Vim peb tab tom nrhiav P75, peb xav tau 75% ntawm 200 tus tub ntxhais kawm, uas yog 150 tus tub ntxhais kawm. Saib ntawm qhov zaus sib sau ua ke, peb pom tias 150 tus tub ntxhais kawm poob rau hauv chav kawm nruab nrab 60 - 64.
3. Nrhiav cov nqi uas xav tau:
– \(L = 59.5\)
– \(nN = 150\)
– \(\sum f_{\text{before}} = 105\)
– \(f_k = 50\)
– \(c = 5\)
4. Sau cov nqi rau hauv tus qauv:
\[
P_{75} = 59.5 + \sab laug ( \frac{150 – 105}{50} \sab xis) \times 5
\]
\[
P_{75} = 59.5 + \sab laug (\frac{45}{50} \sab xis) \times 5
\]
\[
P_{75} = 59.5 + 0.9 \times 5
\]
\[
P_{75} = 59.5 + 4.5
\]
\[
P_{75} = 64
\]
Yog li, qhov feem pua ntawm 75th (P75) ntawm cov ntaub ntawv yog 64.
Xaus
Hauv tsab xov xwm no, peb tau tham txog yuav ua li cas txiav txim siab feem pua rau cov ntaub ntawv sib sau ua ke siv cov qauv thiab ntau qhov teeb meem piv txwv. Feem pua yog ib qho cuab yeej pab tau hauv kev suav lej rau kev nkag siab txog kev faib tawm ntawm cov ntaub ntawv thiab txiav txim siab qhov chaw sib piv ntawm cov nqi ntawm cov ntaub ntawv. Los ntawm kev nkag siab txog yuav ua li cas xam feem pua hauv cov ntaub ntawv sib sau ua ke, peb tuaj yeem tshuaj xyuas cov ntaub ntawv kom ntxaws ntxiv. Peb vam tias cov teeb meem piv txwv thiab kev sib tham no tau pab koj nkag siab zoo dua txog lub tswv yim ntawm feem pua hauv cov ntaub ntawv sib sau ua ke.
