Sut i ddarganfod cymedr, canolrif, modd ac ystod

Ffocws dysgu

Dysga ddefnyddio cymedr, canolrif, modd ac ystod i ddisgrifio set ddata.

Mae'r wers hon yn cynnwys:

• un fideo

• dau weithgaredd

Learning focus

Learn to use mean, median, mode and range to describe a data set.

This lesson includes:

• one video

• two activities

Fideo / Video

Sut i ddarganfod cymedr, canolrif, modd ac ystod.

How to discover mean, median, mode and range.

Nodiadau i rieni

Ar ôl gwylio'r fideo bydd disgyblion yn:

• gallu darganfod y cymedr wrth adio’r holl rifau gyda’i gilydd a rhannu'r cyfanswm gyda’r nifer o rifau

• deall bod y modd yn cael ei ddarganfod wrth drefnu’r rhifau o’r isaf i’r uchaf ac edrych pa rif sy’n ymddangos mwyaf aml

• gallu dod o hyd i'r canolrif, gan roi'r rhifau yn eu trefn, o'r lleiaf i'r mwyaf, a gwybod mai'r canolrif yw'r rhif yng nghanol y rhestr

• gwybod mai'r ystod yw'r gwahaniaeth rhwng y rhif mwyaf a’r rhif lleiaf

Notes for parents

After watching the video, pupils will:

• be able to find the mean by adding all the numbers and dividing the total sum by the amount of numbers

• understand that the mode is found by organising the numbers from the smallest to the largest and that the mode is thenumber that appears the most

• be able to find the median by putting the numbers in order (smallest to largest) and know that the median is the number inthe middle

• know that the range is the difference between the smallest and largest number

Y canolrif yw’r gwerth canolog.

I ganfod y canolrif, rho’r rhifau yn eu trefn ac edrycha pa un sydd yng nghanol y rhestr, er enghraifft:

• 3, 3, 6, 13, 100
• 6 yw’r canolrif

Os oes dau werth yn y canol, mae’r canolrif hanner ffordd rhwng y ddau rif. Does dim rhaid iddo fod yn rhif cyfan.

The median is the middle value.

To find the median, order the numbers and see which one is in the middle of the list, eg:

• 3, 3, 6, 13, 100

• the median is 6

If there are two middle values the median is halfway between them. This might not be a whole number.

Y modd yw’r rhif sy’n ymddangos amlaf.

I ganfod y modd, trefna’r rhifau o’r isaf i’r uchaf ac edrycha pa rif sy’n ymddangos amlaf, er enghraifft:

• 3, 3, 6, 13, 100
• rhif 3 sy'n ymddangos amlaf yn y rhestr, felly 3 yw’r modd

The mode is the number that appears most frequently.

To find the mode, order the numbers lowest to highest and see which number appears the most often, eg:

• 3, 3, 6, 13, 100
• number 3 is the number that appears most frequently in the list, so the mode is 3

Y cymedr yw cyfanswm y rhifau wedi’i rannu gyda nifer y rhifau.

I ganfod y cymedr, adia’r holl rifau gyda’i gilydd, wedyn rhanna'r ateb gyda’r nifer o rifau, er enghraifft:

• 6 + 3 + 100 + 3 + 13 = 125
• 125 ÷ 5 = 25
• 25 yw’r cymedr

Dydy’r cymedr ddim bob amser yn rhif cyfan.

The mean is the total of the numbers divided by how many numbers there are.

To find the mean, add all the numbers together then divide by how many numbers there are in the list, eg:

• 6 + 3 + 100 + 3 + 13 = 125
• 125 ÷ 5 = 25
• the mean is 25

The mean is not always a whole number.

Yr ystod yw’r gwahaniaeth rhwng y rhif mwyaf a’r rhif lleiaf.

I ganfod yr ystod, tynna’r rhif isaf o’r rhif uchaf, er enghraifft:

• 100 - 3 = 97
• 97 yw’r ystod

The range is the difference between the largest and the smallest number.

To find the range, subtract the lowest number from the largest number, eg:

• 100 - 3 = 97
• the range is 97

Gweithgaredd 1 / Activity 1

Ad-drefna’r labeli ar y cerdyn isod i ddangos y cymedr, y canolrif, y modd a’r ystod.

Re-organise the labels on the card below to show the mean, the median, the mode and the range.

Gweithgaredd 2 / Activity 2

Isod, mae sgoriau Louie ar ôl saith twll o golff. Beth yw’r cymedr?

Below are Louie's scores after seven holes of golf. Find the mean of the numbers.